iOS games converted to OS X? No thanks! Original OS X apps with competitive pricing? Yes, please!
Competitive pricing is key. I'm sure the Mac App Store will be a success, but apps can't be priced ridiculously. I hope developers don't plan on charging even more than they do for iPad versions.
If porting over iOS apps to the Mac isn't that much work, hopefully the price will remain low, and the sheer volume of sales will let these developers thrive.