Well, personally I feel most fans are extremely overpriced so I won't be much help there.
I favor the debranded fans you can find on ebay for lots of 4 for $10 or lots of 2 for $5. (Scratch that... seems they doubled in price. http://www.ebay.com/itm/Lots-2-Green-Quad-4-LED-Light-Neon-Clear-120mm-PC-Computer-Case-Cooling-Fan-Mod-/271232219832?hash=item3f26b33ab8)
Aside from those gems, I'd recommend sickleflows or bitfenix specrtre fans (not pro) if you wanna spend $10 per fan. Anything more than that is simply not needed for case fans imo.