As Opt said, Your best bet is to get a split system. Very Quite. Very economical. If your lucky you can get a really cheap one fitted for nothing. The split system just recirculates the air in the area its cooling down. All you need is space for the Condensing unit [Outdoor unit], which means no appartments/flats, unless you want a REALLY long pipe run :P A small wallmounted split system can cool your room down to around 17 degrees.

Over here in the UK i bought a Mitsubishi Wallmounted Air Conditioning 3kW System for £350 [$700?]. Obviously i fitted it myself, but what you looking at being charged in the UK for something like that is around 1 Days work, so basicly what ever the hourly rate is. Estamated £30 an hr. Might sound slightly expensive but if kept well maintained can last for Years.

Abit off Topic, Nitro, Not sure if you remember me. Alastorr from RF Online, Fire Server. Impressive setup hope i can get my shamans as equip soon.