Go for the Thermaltake Volcano 7 + (Note the + (plus), the ordinary model sucks). It's the best performing air cooler out there for the price, looks good and has variable speed (7000rpm being the highest, bearing in mind it makes a hell of a racket at that speed). I'm not sure about the 9 but it's supposed to be pretty good. Avoid the 'orb' style ones like the plauge; they may look nice but their performance is crappy and they cost loads. Go to
www.dansdata.com and check the cooler comp. If you have big money to spend then consider buying a swiftech and buy a fan with it because they're usually not included, but at twice the price of a volcano 7+ and only marginally better performance with a high end fan strapped on, it's not worth it unless you have more money than sense.