The N900 is for all points and purposes now a legacy device.

You will see one - maybe two - firmware updates but then it will be supported in the same way as Nokia supports the N770, N800 and N810 devices. Actually I believe the N900 has already received more support than then N810 did

The Maemo name is already now known to be a dead-end operating system (why do you think Nokia is so eager today to have any reference to "Maemo6" removed?) - and there is NO commercial company out there that will take the time and effort to port and/or create any applications or games for an OS that will cease to be in a matter of, what, a year, eighteen months?

If you should get an N900 is entirely up to you but if I were you I'd look at alternatives like the droid.