Any other things I should consider? For example: how many of each size, what type, and where to put them.
It's Mid-Tower ATX.How many case fans should I have in my Computer Case?
Well if you had included the case name we could give a better answer! Most cases need at least 2 fans one in the front blowing into the case and one in the rear blowing out of the case. The size would be determined by what ever the hole spacing is in your particular case. I personally like ';Variable Speed'; fan as I can change the RPM to move more or less air depending what I'm doing with m computers. Small (80mm) high speed fans a top speed move a lot of air BUT they sound like a jet plane taking off! The bigger 120mm fans can move the same amount of air at slower speeds so as to NOT make all that noise! With the Variable speed fans I can set the speed (and noise) low for general work and hi for gaming! Some cases have places for 6 hi-speed fans and that's great IF you don't mind having a hurricane in your room that sounds like your just behind a big jet as its taking off! Fan measurements are given in three basic ways. 1. RPMs 2. CFM..the unit of measurement of air pressure (moving air) the higher the better! 3. DBa..the noise level! the lower the better! Be more concerned with CFM and DBa you want high CFM with low DBa. Most cases come with fan in them but the quality of the fans may be dubious to say the least! I have the Cooler Master mini tower case (541) which does not come with any fans. It has the ability to accept a 80MM or 92MM or 120MM in the front and a 120MM in the rear. I mounted the Thermaltake 120MM adjustable in the front and rear. Works good for me!How many case fans should I have in my Computer Case?
%26gt;how many of each size,
Generally, a non-gaming case would only support 1 size of fan, and only have about 2 or 3 places for you to screw the fan in.
A good gaming case would have a selection of maybe 2 or 3 different sized fan holes and perhaps up to 6 fan holes for you to choose from.
If you want your computer to be quiet, I would invest in some good quality fans that have ball bearing motors. Arctic Cooling fans are my personal preference, though there are some other good ones made by Zalman and Enermax. Read some reviews.
If you like bling, there are also fans that have coloured LED lights. Looks nice on a gaming case, but they are not so good on a generic one.
%26gt;where to put them.
Pretty obvious where they go. You can only put them where there are fan holes..
This is tough since you already have a case. Most cases come with their fans pre-installed and typically don't have too many spare mounts for fans. But, you could always cut out a hole and scew one in your self if you want to get that extreme.
If you don't already have the case then buy one with several large fans already installed. I have the Antec 900 Two and it is a perfect case for hot systems. Two front 120mm fans, one rear 120mm fan, one top 200mm fan, and optional mounts: One 102mm mount on the side panel and one 120mm mount on the back of one of the removable hard drive trays. I have a 92mm installed on the side panel. Look in to cases that either already have a top mounted fan, exhaust fan, and side panel fan or cases that give the option to mount a fan in those locations without having to drill holes and mangle the case.
This also depends on what proessor you will be overclocking. The cooling requirements for a Quad core 3.4Ghz CPU are far different than that of a Dual Core at 1.8Ghz. You probably won't need a top fan for triple and dual cores below the 2.8Ghz spectrum. But for a triple or Quad Core above 2.8Ghz, definitely look in to a case with a top-mounted fan.
Don't forget the allways important CPU cooler either, the type of heatsink and fan you have for your CPU is very important as well.
Also, for extreme overclocking, look in to water cooling or PCI slot fans.
Bottom Line: For Dual and Triple Cores below 2.8Ghz: Side panel fan, exhaust fan, possibly top-mounted fan for extreme overclocking of those processors
For Triple and Quad cores above 3.4Ghz: Side Panel, Exhaust, top-mount, possibly PCI slot or internal HDD tray mount (not common in most cases)
Atleast two and as many and whatever sizes you enjoy. Fans are fun.