I tried Saint's Row 2, but its graphics were of GTA 3 level, and running much, much more poorly than GTA IV, whose graphics are superior, :/.
Unless I was accidentally playing Saint's Row 1, in which case you can disregard this statement.
Also, Supreme Commander 1 >>>> 2 in pretty much every way. For 2, they removed most of the things that made SupCom 1 a winner, and made the things SupCom 1 didn't win in even worse (voice acting, story). Sure, it'll run on lower-end PC's than its predecessor, but fuck, it didn't have to - SupCom 1 was two / three years ago, computers are better these days.
And they've made lego of all the graphics, stripped most of the badassness out of experimentals, and seriously damaged the epicness of SC1.
I'm sticking with the first, and should buy it (+ the expansion) and try it online. I'll get pwned heavily for sure.