I'm going to echo what several others have already posted.

If I had to choose, today, I'd still go with the N800. I bought one when it had only been out for a few months, and I wouldn't trade it for a N810, today.

Two full-sized SDHC slots are a huge advantage, IMO, and I'm assuming a N800 is a little less pricey, now.

The N810 has a hardware keyboard, which is convenient if you plan on doing much typing. BT or USB keyboards are always an option, and I only use a keyboard with my tablet very rarely. The onscreen is good enough for nearly everything I do.

GPS isn't something I've been interested in. I do fine with downloading my planned route before I leave. I think some people are having trouble with the built-in gps, too. BT GPS may be a superior option, but regardless it's not something I would personally use very often.

My $.02