I don't know if you already chosen to buy a tablet but I thought to write here my impression about my nook color.

I own it for almost 3 weeks and it's awesome. A true value for money. The screen is great, battery life is perfect It lasts over 1 day with continuous usage (all day). I flashed the last nightly from cyanogen and it got better (300mhz-1,2ghz low voltages)! I m sure that it is not a placebo effect. With normal usage it maybe last for 2-3 days. Most apps from market will work, obviously except those which need a camera or a mic. As I had told you, you can use your N900's gps via bluetooth. Accelerometer into some games may not work (eg shaky tower) but most games will work. Also, usb host do work.

If you have further questions do not hesitate to ask me.