Planning HTPC Scratch build needs help for planned cooling

So I am admittedly a fairly long time lurker hoping to get some help on a design and idea that had come to me last year. I want a new tower PC. But at the same time, I already have a nice quad core in a big tower case, so how do I justify this new build without ditching this 3-4 year old tech? Put it into an HTPC and use it in the living room! I was getting all lined up to get my

This in my mind seemed like a great idea, I get a new toy, and I recycle/repurpose the older one (Yay!). But then I rather suddenly became unemployed (boo...). As a result, I haven't been able to buy parts for my new computer, so I never went along with the plan. However, it recently struck me in my middle of the day boredom, that I could go along with the case build, as it wouldn't necessarily cost an arm and a leg, and would give me a renewed sense of purpose and productivity (for those who have never been unemployed for a couple months, it is much needed).

So sob story aside, I have no idea how air flow should work in an HTPC. It, in my mind, is an especially important issue as I will be throwing in a mATX card in there with a full graphics card (my old geforce 9600), and my quad core cpu (Phenom 9600 @ 2.3 ghz) along with a 600 watt PSU. Yes, I could go lower on power, but the goal of my build is 3 fold. 1) Recycle the old PC to build a sandy bridge tower, 2) save money now that I don't have enough income to frivolously spend on both new htpc parts and then later a new tower, and 3) to use it not only as the media center but also as a nice little emulation box as some of my older console boxes are dying on me.

So back to airflow, it would probably be the size of a very small midtower lying on its side so the cpu and mobo tray is on the bottom. It is a scratch build so I have a lot of options, but water cooling and passive IMHO are not viable. I was thinking a 200mm top fan exhaust and 2 120mm fans on either side, front fans as intake and back fans as exhaust, but I really don't know how much that will cycle air across the components, due to the number of ports I want on the front (for game controllers) I don't think I can manage a typical front intake fan. Maybe have only one intake on either side and exhaust out the top 200 and couple back 120's? What are some of your suggestions?

Currently on a laptop for the week, so I can't really get some concept drawings up, but maybe I'll freehand some and post pictures of the plan? Thanks in advanced for all the help you can give a probably over-ambitious Novicaurus Rex.