I purchased diablo 3 for my husband & my video card is not supported so he's unable to play, my computer is a HP P624 f-b desktop with a Intel GMA intregrated graphics, I am aware I need to up my power supply also, I have no idea what video card can be used to upgrade so the game is playable, not looking to spend a fortune
If you want a low profile but totally capable card I would suggest a Nvidia GT 440. It is low profile, quiet, and will not require a power supply upgrade. It is slightly weaker than Area51's choice but will play most games just fine.
If your monitor doesn't have a DVI input, you should be able to get a DVI-VGA adapter pretty easily. Most video cards I've purchased in the past have come with them and I've got over half a dozen laying around.