Here is how I would order cooling solutions based on least cost for a new system with very high end compnents for which cpu, gpu, nb etc.. need new heatsinks:
DIY w/c (under £50)
commercial air
commercial w/c
DIY waterchiller using compressor
DIY phasechange (move up to top *if* you can find a suitable compressor and know what your doing)
Commercial phasechange
TECs.
In order of performance (based on how much the enabled overclock will increase performance in games. GPU counts for about 5x or more than cpu for games, although for encoding video etc. cpu would obviously favour cpu overclock):
DIY phasechange
TECs
DIY waterchiller using compressor (and not TECs)
Commercial phasechange
Commercial w/c
DIY w/c (under £50)
commercial air
Commercial p/c being crap becuase they are cpu only.
Both TECs and compressors (not so much 12v ones) use up a largish chunks of power, so elec. bill aswel..