Yeah, Saints Row doesn't get the kind of marketing or attention GTA does. I didn't like IV as much as III, though. Gameplay seemed more samey/padded.

[quote=Theobromine]
Ib. 
[/quote]

[url=http://en.wikipedia.org/wiki/Left_Behind:_Eternal_Forces]This is what I get when I look up lb.[/url]

Edit: I can't think of a lot of underrated games off the bat. You could name most old RPGs, and it'd be true(Planescape: Torment and the old Fallout's, mostly), but that's true of most '90/early '00 games. Period.
Borderlands was an extremely underrated game, probably still is. Borderlands II got a huge amount of attention because people recognized the name by then, though.