The droid incredible is a really good phone, but the battery life is really bad, and the screens a little narrow for my taste. I like the fascinate's screen (super amoled is crazy), shape and size (4 inches vs the incredibles 3.7 inches i think), though the fascinate is very light weight, and feels like a piece of plastic. *edit: btw the incredible breaks open really easily when dropped, and i'm not a big fan of the red interior beneath the battery door, or the terminator industrial look of the battery door, for that matter, but that's a personal choice. and as far as the samsung goes it kind of looks like an ipod touch, since it's just a black slab.
The other downside to the fascinate is touchwiz, and bing, if you're not into those things, whereas the incredible comes with sense ui, which is popular, and google everything. However, if you're willing to root and customize your phone, you can change all these things to whatever you like.
Cameras are pretty much a tie (8 vs 5 mp not really an issue bc both take very nice pictures).
As for 2.2 vs 2.1, there are probably threads for that.
And what it really comes down to are which features/characteristics are the most important to you.