Just some extra info, one of the silverstones (FM121 I think), emb-papst fmgl4412 (I think that's the model correct me if I got some numbers/letters mixed up) and the Sharkoons are some of the best fans there are. Yate loons are very cheap and aren't very far behind. I've heard tons of horror stories about silenXs breaking and stuff...One guy on XS (masaville) bought some yate loons and it turns out, the yate loons pumped MORE air and were QUIETER than the SilenXs...
Noctuas are extremely quiet but have poor pressure so don't stick them on rads if you happen to have one. All the fans I mentioned have relatively good pressure I believe, so they're suitable for using on a rad.