Building a New Computer

I rarely post in or visit the tech. boards, but I imagine this question is pretty common amongst the lesser knowledgeable Anonymi: What should I buy/look into if I was interested in making a moderately good gaming computer?

My old one, which a friend put together, lasted me for about three years (seems so long) but allowed me to play games like HL:2 and the like with full graphics with no lag whatsoever. Recently, to my dismay, the power supply died and brought the motherboard with it. And I figured instead of replace the two, I could just build a new computer.

It'd probably be too much to ask if I were to hope for posts detailing what parts to get, etc... Instead, if you wouldn't mind, a rough summary of your own current system specs if you have a gaming computer would suffice. I'm not really looking for the omigod four-video card and 4tb hd computer set-up; a simple few month-year old mobo, one graphics card, etc, list would work just fine.

If anyone does help, I'd appreciate it if this didn't turn into a brand troll fest. Thanks.

Just make sure to read outside sources (andandtech, arstechnica, tomshardware, hardocp, etc.) and talk to other gamers, as the reviews on newegg, while they can be informing as to product reliability, there are also massive untold legions of n00bs heralding 1.6GHz Applebreds with 64k of L2 cache and PCI FX5200s as the most awesome things evar because "liek it works, and its fast enough for most people! lol". Keep in mind that YOU GET WHAT YOU PAY FOR.
Side note on graphics cards: The amount of memory they have on them is important, but too many people fall into thinking that it is the only thing they need to think about. Things like memory bus width (128bit is minimal, 256bit is preferred) number of pixel pipelines (at least 8, 12 or more is better) memory clock speeds, core clock speeds, are all important, and some (like pixel pipelines and memory interface can be MORE important than just "lol 256mb"

For example: compare a 512mb X1300 Pro to an older 128mb X800, the X800 would destroy the the X1300 Pro in every conceiveable benchmark, by a wide margin, due to having several times as many pipelines, 256bit memory interface, more pixel/vertex shaders, and much higher memory clocks. And the x800 would only cost a little more due to being "obsolete". In fact, the X800/X850 series (like to GTO cards) are a great way to get to serious graphics power on a tight budget. You won't have the latest graphical bells and whistles (like PS/VS 3.0 or HDR), but you will still get all of DirectX9.0c at good framerates at good resolutions.