I disagree I have a 32" LCD HDTV and there is absolutely NO button lag whatsoever
But as for a TV suggestions Look at Vizio they have really nice HDTVs... and go for LCD because as Maniclysane said plasmas are bad, they burn images onto the screen and also emit toxic gases... so stay away from them and LEDs are just too expensive... I think a nice LCD will be perfect for you..
+ I play my PS3 on my tv all of the time and it's amazing... I also have HDMI cables too
Hold it!
If you play Melee, you will need an Analog TV. Trust me. I know. @ my tourney, I brought my HDTV thinking that everyone would be cool with an extra, only to find out it lags. The lag can be minimized through a passthrough device, but even so, you will notice your button inputs lag by a few frames. Not enough for it to disrupt n00blets in Melee, but a seasoned player will pick up on it very quick.
However, Brawl should be okay for a HDTV. Be sure that you enable the right mode on your Wii, though.
Any other current gen system will be fine with a HDTV.
That's about all I know. HDTV's lag though. It's only a few frames but if you play competitively or are practicing whatever game, don't play it on an HDTV.
Melee lags, I don't think Brawl does. I'll double check on that though.
*Goes to double check*