Last two I rented were MGS4 and Lair. I'm a huge dragon fanatic, but was delightfully unimpressed with Lair's linear gameplay. I'm not a huge fan of MGS4, but I enjoyed playing it more than Lair.
Honestly, I'm glad I rented, otherwise I'd have wasted $60 on a game that would have collected dust. Something like what my GTA4 is doing now in favor of my Burnout:Paradise and WoW habit. *shrug*
Honestly, renting makes sense. Especially if you don't know if you're going to like the game. Sure, some people will say "You're spending extra money on a game by renting it! zomg!" ... Uh .. no. Not really. In the long run, if the game is interesting enough that I actually play it during the week that I have it, then it stands a good chance that I'll buy it; however, if I don't play it, or worse, I return it within a day, then I've saved myself money on buying a dud. So far, the "shareware" concept works for console games.