My friend has a watercooling rig, and apparently it can be quite high maintenance (cleaning the reservoir etc) and unreliable. I've always strived to get the best balance between a cool PC and one which isn't gonna keep me awake at night (my PC is never off), and have definitely had some vacuum cleaner-type cases in the past.
Currently, I have a Lian-Li black alu case which is excellent, and before that I had a Shuttle XPC which was also really quiet and portable, although not very expandable. The difference between these cases and my older ones is that they simply have the right amount of fans required, unlike my old ones which were pretty OTT and really had too much cooling for their own good - though of course they might be great for overclocking gurus.
Hell, my Shuttle had 1 fan/heatpipe combination and nothing else, though it was my second most stable PC ever behind my current one (this one has had a week and a half of uptime in one stint before it needed a reboot for instance).
Just make sure you know what you're getting yourself into buying cases with uber amounts of fans is all I can say
