So far this season I've played The Force Unleashed, Viva Pinata 2, Fable II, Saints Row II, Rock Band 2, Midnight Club, CoD5, Left 4 Dead, Banjo and GoW2 and there isn't a single game in that list that I would recommend over Banjo @ $27. The game is huge, the graphics are pretty, there is humor, you can play it a ton of different ways, the building mechanic is completely fresh and works great and the variety in the gameplay is awesome. For a fun/value relationship it can't be beat. It matches my memory of DK64 in every way.
You are much better off buying this game now and waiting to play other new fall releases until they get a price drop later on. This game will only drop 25% in price whereas most other titles will drop 50% or more.