Forget what you read. Basically the sharper the lens, the sharper the image will be. That pretty much means the more expensive the lens, the sharper the image will be.
The talk of cameras or lenses "outresolving" each other is mostly junk and comes from people repeating what they've read or from people without a good understanding of optics.
You might want to read this article which goes into a little more detail on the subject:
http://www.bobatkins.com/photography/digital/canon_eos_50D_resolution_confusion.htmlSo just buy the best lens you can affford and don't worry about what "outresolves" what, because it doesn't!