i have one of those noctua fan on my pc, and what i can say... its perfect. even cooler master thermaltake can do better job than noctua. but the price! worst cooler i have its from spire blue max. even a 1200 rpm make noise.
Have 2 of the 80 in my HTPC with the low RPM adapters, fantastic little fans. Also have one of the tower coolers in my gaming rig. awesome stuff all round.
PWM versions and standard versions of their whole range would be a great lineup IMO.
Noctua fans, especially their PWM series, are awesome. They are really superior fans. I don't even mind the colors, I never use windowed cases, I couldn't care less about appearance of internal components. Performance, quality, noise - that's what really matters, and Noctua is the best.
Unfortunetely, they charge a serious premium for it. I can't typically recommend them for cheaper builds (or any build where maximizing FPS on a fixed budget is the only concern) as a result.