Re: bottom intake
I thought about this also. I didn't want a bottom-of-the-front intake because I bought a noisy (Maxtor) hard drive by mistake, so wanted any openings to be a long way from it.
I put my intake on the back & added a baffle so the air flows in a U shape from back, around the front, and back out the back.
My DigitalDoc 5 measurements show that the sidesinked & suspended hard drives do run cooler with the U-shaped airflow than with the case open, but if I were concerned about CD & DVD temps, I'd probably add a vertical baffle to force air to up to the front-top of the case before coming back down to the CPU and power supply.
My video card is passively cooled, so covering the back with the baffle isn't a big deal, but I've notice that some of the new cards have not just active cooling on the front but some passive on the back. Old card was a Matrox G200, new one is a Radeon 7000.