> Of course, the lens you put on the DSLR makes as big a difference as you're willing to invest. That's why they'll never really be comparable.

For a layperson, I don't think this is true. It takes a professional to extract the extra difference between say, a 50mm f/1.8 (~$100) and 50mm f/1.2 (~$1500). In fact, if I handed them both to a newbie, I'd expect them to do better with the 1.8. Myself included.

That said, the f/1.8 is a bit exceptional, especially for its price.