I'm seeing some good deals for Bioshock Infinite on the PC, maybe with the chaos of Sim City and the disappointment of the Aliens game people have been reluctant to put as many orders in for this over the last few weeks.
I feel this one in particular needs your attention. As it's single player anyway there's more reason not to get it on the 360. For the UK at http://www.greenmangaming.com/bundles/ it's £23.99 for 4 games. Bioshock Infitite (with the Industrial Revolution pre-order flash game and bonuses), Bioshock 1, A choice of 5 games (Civ 5, Mafia II, Bioshock 2, Darkness 2 or Spec Ops: The Line) plus XCOM, one of last years most highly rated games. Not sure of the exact dollar price but I believe in the US you also get $15 store credit too.
Steam have almost the same offer but a little more expensive, it seems GMG added XCOM to the bundle as a response to Steam including it, it makes it a superb deal though. They are all steam keys too I believe and work with a 360 controller (except Civ 5 I guess)
I picked the Mafia II bundle, but might not make use of it so I could use it for Steam trading in the future. No shortage of gaming for a while now.
Referral link: which adds £2 to yours and my account if you aren't already registered and decide to buy from them http://www.greenmangaming.com/?gmgr=culezeki
Oh, and here's a bonus Beetlejuice rollercoaster from Minecraft on the 360.