I have an Antec 900 (great for cooling, POS for building). I built my system with a 680i, e6300 (now e8500), 2gb ram (now 4gb), 8800gts 640, x-fi platinum (with the front break-out box), 2x wd2500 hdd, a combo media reader/floppy drive, a plextor 755sa dvd burner, and a pcp&c silencer 750 quad sli. my cpu cooler is a true 120 with a scythe 120mm fan.
the 900 has three front drive cages, each with a 120mm fan with h/m/l speed selector. I used several combinations of how and where I installed the hard drives, the break-out box, the combo drive, and dvd burner. in order to maximize the use of two fans in the front, I had to put my three external devices into one drvie cage. I moved the other fan (from the front), to the side panel.
I experimented with layouts and fan speeds and determined that the only fan that made any real difference was the side fan.the front two fans did not help lower temps when speed was increased, so they are set to low. the side fan is set to medium, a good balance between noise and cooling. the top exhaust fan is at either low or medium (I don't remember), and the NB fan is set to about 50% (any higher and it gets very noisy).
the true 120 is setup so that the scythe fan is at the bottom and sending upwards and towards the top exhaust fan. the side fan and the scythe interfere with one another, but all I had to do was to cut-off an inside corner of the side fan housing and all is well.
with this setup, I was able to OC the e6300 to 3.25 stable, and the e8500 to well over 4ghz (I don't remember the exact number). my apologies for I don't remember what the temps were and currently I am running at stock speeds.
I am getting ready to build a new system with an x58/1366 mb, a gulftown cpu (if performance warrants), a 5870 (unless something new comes along), massive amounts of ram (currently looking at 12gb), two 300 velociraptors in raid-0, and a wd 1tb backup, all in a haf-922. I am using the lessons learned from my current build and am adding two 120mm fans to the side to cool the gpu and other components. the cpu cooler is going to be the cm hyper 212 plus.
so I guess the bottom line is that if you're air-cooling, get a case with a big top fan and which can accomodate two or more side fans, and add a kick-ass cpu cooler and you will be all set.