|Your case may handle a larger fan, but if it does not, look for a quality ball bearing fan with a high CFM but a relatively low noise (DB). A front fan can be useful because it blows air directly on your hard drive(s) and towards your video card. As long as your rear exhaust fan plus your power supply's fan moves more air out than you are pushing in the front, you are in good shape.|
Remember that in moving more air through your case, you will have to check it more often for dust build up, but keeping it cool is important. Use a can of compressed air to blow out the dust every three to six months or as needed.
You have to be a little bit crazy to keep you from going insane.