Last week I picked up the Xbox 360 wireless racing wheel since it was $60 off, and I figured I'd be buying Forza eventually. This past weekend I picked up Forza 2 and put quite a bit of time into it, and my conclusion is that it's the most satisfying racer I've ever played. I know I sound like a gushing fanboy, but it's seriously just so much damn fun I can't help it. The funny thing is that I've never been too big into the simulation racers, and have traditionally been a fan of arcade driving games like Ridge Racer.
I think without the wheel I wouldn't be too interested in Forza. But combined with the wheel and the realistic handling, it just comes together so beautifully that it's just a joy to drive. Even my friends who aren't big into racing games at all were having a blast just playing one track over and over again. The wheel communicates the feel of the car so well since it's force feedback so you have to fight against it and deal with losing grip and everything.
I'm still pretty early in the career mode, but I'm obviously already having a ton of fun with the lower end D and C class cars. Right now I'm sticking to Audis and their all-wheel-drive situation since it prevents spinning out. I prefer AWD or FWD since those are easier to control. I tried out a Lotus Elise RWD and just kept on spinning out everywhere. I'm not going to give up though, I've read some tips on how to tune a RWD so it's more controllable. I refuse to turn on traction and stability control. I'm working on eliminating ABS support as well.
I really can't recommend this game enough to any driving fan. But it is a significant investment when you add in the wheel, so be sure that you're really going to play the game for a while before picking it up.