What should I be looking into at first?

Something around 50 inches... sound I really push for HDTV?

For the sound system.. its a tile'd room and about 20 by 20 feet.

 

If you meant ...should I really push for HDTV, then YES, absolutely. If your going with a TV that large your are going to be spending more than a grand. If thats the case then you wont want to be buying another one in 4 years when HDTV is everywhere. Go for it, but make sure its HDTV and not EDTV, which by itself isn't bad but just isn't the best out there.

As for a sound system get advice from others on this board as my experience is limited. But with a tiled floor you may want a downward facing sub that bounces the sound off the floor (only good with hard floor, carpet kills it). I had one of these and it was great because it was hard to tell where the sub was because it made the sound fill the room.
The last thing you want is to be distracted by the subwoofer pounding away.

 

The tiled room is going to really hurt alot of the sound stage than you may try to generate from a pricey system. You may want to go for asthetics instead of perfect sound due to limitations in room acoustics.

 

How much do you want to spend total?
How far from the Tv will you be sitting?
Any light in the room?
Any funny angles the TV will be watched from?
A significant other restricting the aesthetics (aka size) or the speakers?
Can you describe what the room will be setup like, aka a sqaure with the couch in the middle and the TV centered on the wall, or will the TV be in the corner and one wall is open, that kind of stuff.

Answer these questions and I could probably put together a killer system for ya.

 

Forgot to ask, divide 100% of your time using the system between music and movies.

 

My advice? Appreciate that there are different forums for different specialites/interests. And given the interest you're indicating here, I would direct you to find all your answers at http://www.avsforum.com/. Lots of good direct links as well as general forums too.

Good luck! Wishin' I had some o' dat money to burn .

- Dave

 

Make sure that you put a throw rug on that floor. It wouldn't hurt to get some items on the walls that could help to dampen the sound reflection as well.

Good luck!