I own Nook Colors, Viewbook 730, gTablets, Ziio 10, and a Chinese (8650) tablet. You have lots of information in this thread that gives you the basics of comparison.
Here's my view:
Nook Color has an active and capable development community. This makes you tablet worth a lot more.
Nook Color (used) can be purchased for under 200 and closer to 150 if you're careful. If you leave it at your buddies house and he sits on it you are not going to be forever embittered.)
Nook Color has a capable processor, particularly overclocked, and this makes it a pleasant sxperience.
Nook Color has a beautiful screen in a great form factor for ultra portable use. (I can hold it in one hand easily and carrying it into McDonalds or IHOP without worrying about dropping it or fumbling with it while I pay my bill.)
Nook Color has ample onboard and allows for off-board storage.
All of the above make it my number one choice in a 7" tablet.
My wish list for the NC would be a webcam (and mic) and the ability to do full video skype. A better bluetooth would be nice as well but I'm OK in this format without it.
So, all said, if you're looking for a more portable and affordable and capable experience than an iPad or one of the dual core Androids, get the Nook Color and root it.
If you really are looking for a multimedia device and you just don't want it to be a netbook, then go with the gTablet if you want it around 200 or go for the best in the Asus Transformer at 450. Those 10" dual core machines are really nice to use. But be warned, these are not netbooks. A netbook is still your best choice if you're looking for multimedia and terrific functionality. Tablets are more a fancy crosswork puzzle and news consumer device. They are fun and I really like them, but they aren't as capable as a netbook.
