Sound is a factor, but for me it's far less important than the feel, although I do like more quiet boards. I like the sound of a Model F, but for my MX boards I always trampoline mod them and usually also latex mod them, so they are damped on both bottom out and release. Then I like the sound they make, a more subdued clickety clacking that seems to speak of higher quality somehow.
The silenced Topre boards sound okay, too, but I don't like how the switches feel.
I really don't like the cheap, plastic sound of MX clicky switches.
Alps clicky switches are a lot better, but I don't like how they feel (at least the ones I've tried so far), so again not for me.