Sparkle / Nexus / Zalman - all good
Ive heard the Nexus 120mm fan model is actually quieter than the Zalman PSUs . . . havent heard either myself, but the Nexus seems a bit pricey?

Ive thought about the ebuyer Superflower4 fan PSU's . . . seem to be good value for money and Ive read reviews on them (they're called something else in Asia where I read the reviews) saying they're pretty much up there.