Dribbble is neat and all, but using it to find a designer is like picking a book by looking at the lower lefthand corner of the cover--it doesn't tell you anything. You might find a designer who is good at fancy effects in photoshop, but it won't tell you much about UX, architecture, coding experience, etc.
Dribbble could be the start of your browsing experience, but should by no means be viewed as the go-to place.
- I hate cats - the hair, the smell...
- Oh, you just don't know a good recipe
Nobody is saying that one needs to pick a designer because of that one 400x300 shot that looks awesome. What the OP meant is that Dribbble is a great visual directory of a metric ton of really good designers.
I stand by my affirmation that it's the single best place to find a designer.