I'm finally joining the XBO club. The Halo/COD/Forza bundle for £350 made me cave, mainly due to Halo. I'll finally be able to play Killer Instinct!
If you like platformers then Rayman Legends is a great game to pick up on the cheap, Dead Rising 3 is also brilliant fun and can be had very cheaply these days.
EA Access is well worth signing up for as well. For £20, you'll get Plants vs Zombies, BF4, Peggle 2, FIFA 14, Madden 25, NFS Rivals for free, plus 6 hour trials of the full game of FIFA 15, NHL 15, Madden 15, NBA Live 15 and the new Dragon Age in a few days time.