1. Graphics cards (or more accurately GPUs - graphics processing units) are basically made by only two manufacturers: ATI & nVidia. All the other brands you see are resellers who put they own unique branding, fans, etc on them.
2. You need a PCI Express (PCI-E) GPU as that's the best & cheapest. PCI is the actually the worst, & to use AGP you need an AGP slot which your motherboard will not have.
3. An ATI HD 5450 click here should be good enough. Not only do most of them have 3 types of output (VGA, DVI & HDMI), but they are also passively-cooled (fanless) so don't emit any noise. To use its digital connections (DVI/HDMI) to view Blu-Rays, I think your monitor needs to be HDCP compliant. If not, you can only use its analogue (VGA) connection.