First of all, this is just £25 when purchased through Amazon with an XBox 360...
Right, onto the games. Forza is a really great driving sim. I prefer it to PGR4 so far, although the menu system and possibly also the career mode is slightly better in PGR4. That said, it's all about the tracks and the races, right? This is as good as a Gran Turismo in my opinion and a lot of the tracks from the GT series are used, making it easy to move across . . .
I've only played Viva Pinata a little but it is a lot of fun and seems like quite a deep and involving game. If you're a fan of Animal Crossing, The Sims or other games in this ilk, this'll be right up your street.
Finally, the controller . . . it's wireless and you really don't want to get a wired one in this generation now, do you! As good as the old Dual-Shock and the new SixAxis in my opinion. I hated the original XBox controller and didn't buy the console as a direct result. This has a really good feel to it, the asymetric analogue sticks fit nicely and two triggers on the shoulder make it ideal for FPS games.
It's a great addition for your 360 purchase, although like others say, can probably be found cheaper if you are NOT also buying your 360 through Amazon.