I did that (on my old white xbox) the day i got Black Ops....the cat knocked my xbox over & destroyed the disc!
Amazon actually just replaced it for me, event though it wasn't their fault, was just because it was release day i suspect. So if you've recently bought it, you could try it.
The professional option is worth a punt though. It probably won't work because its not so much a scratch, more of a gouge....but worth a shot if it means you don't have to rebuy (or you could borrow the disc from someone else & copy it to your HD, and just use your own disc to verify you own it when you wanna play if that makes sense).