jupstin--
I love my new Sony 650!! Love the touchscreen interface. In my opinion, Sony did a great job making the interface super intuitive. (Again in my opinion--much better than the nook I also own.) I use the dictionary frequently--and it's great to be able to double tap on a word and have the definition pop up at the bottom of the screen. (One of my favorite features.)
My MIL has the 350--and at first I thought the 5" screen would be too small--but not so. I was kind of hoping she wouldn't like it, so she'd give it to me--but no such luck!
If you're interested in wikepedia look up, I'm pretty sure the new Sony 950s will do this--I think it works in much the same way dictionary lookup works on my 650 (someone correct me if I'm wrong).
Good luck making your choice--I really don't think you can make a wrong one!
dordale
Downside to the Sonys--they are more expensive than other models. But, I've compared my 650 to a co-worker's K3 and the 650 seems to be more solidly made (and it's smaller too--because it doesn't have the keyboard). Also the 350s and 650s don't have wi-fi (I think a misstep on Sony's part.)