This isn't a bad deal at all. Buy HALO 2 (PC) for $40 at Circuit City and get Shadowrun for free. $40 isn't a bad price. Getting Shadowrun (which I think is a ton of fun) for free is like getting both for $20.
If you bought HALO 2 (PC) from Circuit City lately, you may be able to do a return and rebuy if you haven't opened the game yet. Doing so may allow you to get the Shadowrun deal.
I'd hit that.
I'd hit that.