Keyboards are one of the most important aspects of any computing device second only to screens in their importance. Unfortunately due to death of Nokia, Palm, Motorola corporate transitions and the death of other phone manufacturers who made devices with physical keyboards and due to the death of the UMPC product category portable devices with keyboards have become a rarity. Unfortunately old devices can't be kept alive forever due to software support and eventual hardware reliability issues. To be fair though good physical keyboards on portable devices were always a unique because before touchscreens were the dominant input method T9 was the dominant input method and all touch devices existed before Apple and Android.

Physical keyboards on laptops are not disappearing but definitely degrading in quality. The trend towards ever thinner computers has not only come at the expense useful ports like ethernet and full sized ports but also at the expense of keyboards. This is in my view an example of usability being sacrificed for the sake of design.

Here is my list best mobile devices with keyboards and best keyboard addons as well as the best and worst laptop keyboards (in my experience).

Devices With Keyboards Built In

LG Optimus F3Q/LG Enact
The Optimus F3Q is lower end in terms of specs but it is an option for those who need something lower cost. It also one of the few devices that is a slider. The Optimus F3Q sells as the LG Enact on Verizon for those CDMA users. It is kinda hard to find though, so keep that in mind. Like the n900 the F3q has an IR blaster.
http://www.gsmarena.com/lg_optimus_f3q-5998.php
http://www.cnet.com/products/lg-optimus-f3q/

Neo900
An upgraded Nokia N900 with a different Motherboard and some other features. Covered in depth in this thread here. Not as good in specs as other devices but is another option for fans of slider keyboards.
http://talk.maemo.org/showthread.php?t=91142

OpenPandora and Dragonbox Pyra
The Openpandora is an actually existing product but it has very outdated specs and is very hard to purchase. The Dragonbox Pyra is an upcoming product with upgraded specs. Both the Pyra and Pandora have a unique clamshell form factor with both game controls and keyboard. There is really nothing else out there that is similar. In the case of the Pyra it is still in development, so one will have to wait. If it becomes available then I might purchase one for myself.
http://pyra-handheld.com/
http://boards.openpandora.org/page/homepage.html
http://en.wikipedia.org/wiki/DragonBox_Pyra

Blackberry
Blackberry has many devices with physical keyboards for every single niche. Blackberry has the Passport at the high end, the Classic at the mid range, and the dev Alpha C, Q10, Q5 for the low end. Blackberry makes no slider phones but Blackberry's have all the features of any modern smartphone with there Blackberry 10 os.
Blackberry is covered extensively in this thread here. Blackberry's are good for people who prefer physical keyboards but don't like sliders of clamshells, many have used the older Nokia E-series such as the E71, Classic Blackberries and Palm Treos and many of the people who own those devices have yet to upgrade. Blackberry might make a slider device and is possible developing an entirely new form factor with the Blackberry Visa. Blackberries are also good for people who want good support for their devices, many of the other fore mentioned devices are niche devices and won't get good support. Also if you hate widescreens like I do, then they are one of the few options out there.
http://talk.maemo.org/showthread.php?t=94148

If none of the devices mentioned above interest you then there are several options in the form addons. Tablets have the widest array of options in terms of addons, however there are a lot crappy ones. Phones have fewer options when it comes to addons but there are options if you look hard enough.

The Other Half Keyboard For Jolla
The TOHKeyboard use the Other Half of the Jolla device to connect the Keyboard. It was funded through a kickstarter and I am not sure when it will be available for general purchase or if it will be.
http://funkyotherhalf.com/
https://www.kickstarter.com/projects...for-your-jolla

iPhone keyboard cases
I am not a fan of iPhones myself but they have a good selection of keyboard cases. Though do keep in mind that they tend to cost a lot of money.
http://www.cnet.com/products/typo-iphone-keyboard-case/
http://www.pcmag.com/slideshow/story...hone-5-cases/4
http://ipod.about.com/od/introductio...for-iphone.htm
Samsung Keyboard Cases
Samsung devices being very popular also have a variety of keyboard cases. Keep in mind that touchwiz and many apps are portrait orientedand using said cases tends to block out the camera. Despite the design quirks keyboard cases for Samsung devices are of good price and quality and are widely available. I personally like the ones for Samsung devices as they resemble Touch Pro keyboards.
S5 Model
http://www.mobilefun.com/45647-galax...case-black.htm
S4 Model
http://www.androidauthority.com/gala...d-case-223288/
S3 Model
http://androidspin.com/2013/09/15/re...ung-galaxy-s3/

Generic Compact Keyboards
http://www.amazon.com/Fosmon-Portabl...dp/B00BX0YKX4/
http://www.amazon.com/Asmart-center-...dp/B00LL5HVWS/
http://www.amazon.com/Anpower-Wirele...dp/B00G9U0U6E/

For 7 or 8 Inch tablets. These are model specific but should work for any 7 or 8 inch tablet. I have the one for the Note 8.0 and it works well as a thumb keyboard and not so good as a touch typing keyboard.
http://www.amazon.com/Exact-Bluetoot...dp/B00EXSMSNM/
http://www.amazon.com/Galaxy-Note-8-...dp/B00I078G10/

For 10 inch tablets my favorites are either Zagg or Logitech keyboards, though they tend to be on the pricey side. There are also folding keyboards that work very well and Microsoft makes some good ones too.

Laptops

The Very Worst
Acer Keyboards aren't unusable but they have very poor durability with broken off keys being common and are very shallow with little key travel. Acer keyboards are especially bad on smaller models like the S7 which have small rows. Acer keyboards also waste a lot space leaving a lot area not used by the Keyboard. Acer needs to redo this area entirely. Tech reviewers consistently criticize Acer keyboards. My experience with Asus or Toshiba keyboards is pretty similar to acer ones which is to say not that great.

Touch keyboards. The touch keyboards on the Dell XPS 11 and Microsoft Surface line up. These keyboards lack tactile feedback and are pretty much pointless to use. The experience isn't much different than a virtual keyboard.

The Mediocre

Apple Keyboards have a decent layout and key size but the pitch of the keys is a bit shallow for my taste. Overall not the best but the not worst.

Samsung Keyboards. Samsung improved their keyboards a lot but they still lack pitch and key depth. Like the Apple keyboards not the best and not the worst.

The best

Dell Keyboards. If you prefer non chiclet keys Dell still make several laptops without them. Latitude and Alienware products have traditional non chiclet keyboards. The latitudes have trackpoints and alongside the traditonal key layout. On Inspiron products regular Chiclets are used and on XPS products chiclets with curved keys are used similar to Lenovo keyboards. My experience with Dell Keyboards has overall been positive.

HP Keyboards. HP has pretty much standardized on chiclets, however HP's chiclets despite not being unique are better than others having better key pitch and having excellent layout. Even 10 inch HP netbooks have good keyboards. HP business models have trackpoints for those who like that feature.

Lenovo Keyboards. Be it Thinkpad or Ideapad products I prefer Lenovo keyboards though the layouts take getting used to. Similar to the Dells Lenovos have curved keys that are isolated and have trackpoints on Thinkpad models. Avoid the newer X1 carbon with its adaptive row, the implementation is very poor.

Sorry for the length, but the intention was to be to extensive. Keep in mind my judgement and opinions of various keyboards is based on my experience with them so yours might be different.

Keyboards are certainly not dead be it on laptops or mobiles devices if you look hard enough. People will tell you to just use virtual keyboards or swype but even though I can proficiently use virtual keyboards I am not as fast or accurate, I am constantly correcting mistakes. I still find swype to be confusing and in many cases it lacks accuracy. Nothing beets the tactile feel and muscle memory keyboards offer. Physical keyboards also offer easy to use keyboard shortcuts, I have become a master at them. Virtual keyboards also hog screen space as well.
If people vote with their dollars and buy either keyboard addons or devices with keyboards than manufacturers will have to respond. I also don't see keyboards on mobile devices being inherently niche even if they are today as millions people have used PCs with keyboards and millions of people own feature phones with keyboards and don't own smartphones. So the future is NOT hopeless for keyboards.

One Of The Things I Got For Christmas
I converted my tablet into UMPC. Even with the keyboard addon the device is still pocketable.