I've always enjoyed simulator games, like Train Simulator 2014 and Microsoft Flight Simulator. Honestly if Farming Simulator 2013: Titanium edition comes up on sale on Steam at any point I'll be all over it.
Not remotely a guilty pleasure! Have you played Euro Truck Sim? Because you should.
I downloaded the demo, but I've been too lazy to move my wheel to my computer to really try it.
Anyway, if I were capable of guilt I suppose my guilty pleasure would be The Lake House.