Hi Prom, good to see ya in good form

Welcome to xtreme m8! Great place to be indeed!

Back to the chase now

I cannot agre with sandman. If you make connections the right way (if they are made poorly it additionally oads PSU beyond any control and may cause it to burn..) and you're not loading it excessively (more than 105-110% of rated amperage/wattage - you can draw more amps from 12v if it's the only line which is loaded).
I've been running my setup (see my sig) from a single ENermax 465 431watt rated PSU for quite a while (MCW50-T and ~10amps of fans are powered from separate Chieftec 300watt weakling), been overvoltig RDRAM and CPU heavil and as far as now everything is fine (12v line voltage is slightly below 12 volts).
I mentioned connections since the one provided by Swiftech just burned...

About fan placement. Imho using sth lke Zalman's bracket is the best you can, especially with 120mm fans (weight and vibrations the produce).
Don't forget about dcting/shrouding - it'll allow you to use all the cfms your 120 bruiser can produce.

Condensation proofing - you know your stff since you used chilled water setup before