Lucky you.
I would vote for the panasonic PX60 Plasma 42 inch. This is a top-rated TV in Consumer reports. Make Best Buy match the Circuit City price (~ $1200). Also, there are lots of other 'rebates' at Best Buy for delivery and other stuff that you need to look at.
Secondly, spend some of the $$ on a Home Theater system. Best Buy was (and I think still is) offering a free wireless receiver with the Panasonic Home Theater systems. There is a compatiblility advantage buying the same brand TV and Home Theater system in terms of the remote control compatibilities (a minor issue).
Don't forget the Stand!
Lastly, you could probably use a new computer...
If you cannot spend it all, let me know.....