Please find me a list that shows 30 games that *actually" play in 720p/1080i
Some are labeled as such but do NOT output in HD.
The only ones I can think of are The Matrix, Dragons Lair, Syberia, Amped 2, and some MX game(forgot the name). Thats 5, I cant imagine there being much more than that.
I think a basketball game did and maybe Soul Calibur II? Some cases had 480p blacked out but they played in 480p, if people are making lists going by the back of cases, they are clueless

There are actually about 30 something 720p games.. before getting my 360 I was obsessed with finding these games no matter how bad they were... just for the HD resolution.
MX vs. ATV Unleashed
^I own and have personally tested all of those games and can assure you they will run at 720p
as for 1080i... there is only about 4 or 5 games that I know of. Even still, it's hardly a substantial portion of the catalog and with the exception of SC2, none of these games are known for their impressive graphics.