I've been tempted to buy shadowrun ever since I played the demo. It played totally different from most shooters. With the weapon, magic, race mixes there needs to be more going on in your mind. The biggest worry I had was that no one would play it. It seems the Xbox forums are buzzing with cultish followers of the game, so I guess I don't have any worries there. I'm looking forward to getting to play it and I'm wagering the cross platform achievements will be even esier from the Windows Vista side.
Here's the link if you want to buy it yourself. Note, it is Vista only and does require a decent system.