Can anyone help me out?

Hey guys, im real excited for two games that are coming out ON THE SAME DAY..Mass Effect and Rock Band. Im getting both either way, but I am going to buy one for myself to keep my occupied until Christmas and then the other I will get for x-mas. My problem is, I can't decide which game to buy for myself on the 20th, Mass Effect or Rock Band? I do have enough money for

both..but I need to buy Christmas gifts for my parents, sister, brother, neice, and my brothers wife. So anyway, what would you guys do? Would you rather have Mass Effect in your hands on the 20th and have Rock Band (just the game..not bundle)

Christmas morning? Or would you rather be holding Rock Band in your hands and waking up to Mass Effect on Christmas? This is a real hard one for me..

Would you be getting the bundle set for Rock Band? from what I understand the individual instruments wont be out until next year. Unless you plan on using a GH controller.

Whatever the case is, get Mass Effect.