Congrats! Next you'll be upgrading cable/fiber/sat. options.
At the first of the year I did the same thing. Went from a 32" tube for the main TV to a 50" Panny then started on home theater stuff. Also being a cheap ass, I saved over $3000 on the plasma, receiver and all 7 speakers and sub. The sub is the only thing I really couldn't dig up a great deal on, but the company sells direct only now and for more than competitive prices compared to others in the higher end market.
You'll never see the evening new the same way again!
HDTV does trip a gripe in me though. In my opinion it's the biggest farce and scam pulled on America in some time. Go to the FCC (fcc.gov) and dig in to their files on how this all came to be. You'll probably get PO'd too. Againin my opinion, lots of fallacies buried in there. In the short end of it all, it's all about the $$.