I would rather not recommend a PCI graphics card, unless you only need minor uses (such as no more than 2048x1536@50-60Hz res), since most PCI graohics cards don't have dual link DVI's (30" LCD's need them for native res, 2560x1600), and the PCI bus can only be a maximum of 33MHz, and most graphics cards, even cheap old ones, run well over that (usually 200-300Mhz for the really cheap ones). Like someone else said, it would be much better if you had an AGP slot (8x is for video cards, and runs at 533MHz) tutorial, or even PCI-Express (1.25GHz) or PCI-E 2.0 (2.5GHz), seeing as they're the current standard. That would make it less likely for the less computer-savvy to accidentally waste their money on products their slots can't fully use to it's potential.
Also, like Desir0 stated, drivers installation and BIOS settings (to turn off on-board video for compatibility reasons) are a must.
If I were to rate it, I'd give you a 3/10.
6/10 for clarity; you need to show a little more of what you do.
3/10 for information; you boxed the Power Supply screws as needing to be unscrewed when that's totally untrue.
1/10 for detail; you totally forget about drivers installation, BIOS, and even compatibility. This is the worst part, especially since there are games that can't be maxed out without DirectX 10. You also needed to explain why DirectX and OpenGL are used and what they are, and classifications of memory, why more is sometimes better, and other times not worth the price, and an explanation of input (such as VGA, DVI, SPDIF, HDMI, etc), even if just a touch, would have been nice. Another thing that would be appreciated would have been which cards to look for. Most cards over $600 are workstation cards, and are usually poor at gaming, so an explanation of why they're not meant for standard personal use (unless large, 10GB+ 3D design projects are standard) would be a plus. Setting the power supply up for the cards is yet another skipped step. Most new video cards today use their own power connectors, where even a mention would have made a lot of difference.
2/10 for layout; it just isn't appealing and makes it harder to absorb the information. This isn't as important as above, but it's still a big factor when reading. At least there were pictures present instead of a giant wall of text, so I gave you an extra point.