I honestly don't think there are that many games out there worth paying these game devs. I would say CoD4, MW2, Rock Band 2, and Madden 10...thats all that would be on my "buy these games" list. Everything else is maybe worth playing for an hour...2 tops. If they want more sales, they need to make better games.
People that have modded xbox's are going to be buying MW2 bc they know it's going to be a quality game like CoD4. Yes, some have and will burn it...but at least a lot of modded xbox owners are actually buying it. I don't think any other game can say that.