I played my 360 on SD tv for awhile but soon as I bought my ps3 I upgraded to full 1080p HD glory!!!
And I'll never look back. I didn't think I'd notice too much of a difference, but boy, was I wrong! Afterwards, I went out and replaced all my SD tvs with HD & upgraded to HD Direct TV.
My favorite is my gaming rig: 60" 1080p Sony SXRD
PSN ID: Sorrow880
Gamertag: Sorrow80
Wii #: 8132 1076 3416 7450