I haven't used the Enermax temp sensitive fans, can't see any advantage because of their slow response to temp rise. Full speed at 45C won't do your computer any good....
I do believe in quiet computers, however, and have used Adda, Panaflo L1a, Silencers and low speed NMB's. That list is pretty much from strongest to weakest, and from loudest to quietest. Any of these are readily available and inexpensive, unlike the Papst fans that are tres expensive and hard to find.
Don't trust the manufacturers' noise/cfm ratings- some of them are, uhh, a little optimistic. It's all in the power consumption figures, none of them have any magic bullets to defy the laws of physics. Adda-.12A, Panaflo-.10A, Silencer-.08A, and NMB-.06A.
Given that you're probably heavily overfanned with 5, the nmb's should do the job just fine. In a different box with one or two fans, you'd want the Addas or the Panaflos....
Phamcomputer is one of a few carrying the Addas, the panaflos are widely available...