Just got a new HP PC from Costco. Has full HD monitor. Well thats great except there isn't any HDMI slot on the back of the pc. Not a gamer, so what grade of card will I need to at least pass up the on board Intel 3100?
If your computer has a DVI port, you can buy a DVI -> HDMI cable for about $5. If you're going to have to upgrade to a video card anyway, you can get one with HDMI for $40 and up (example: http://www.newegg.com/Product/Product.aspx?Item=N82E16814121302). One thing you should look for is HDCP if you're going to watch any Blu-ray or HD-DVD from the computer.
If the monitor has a DVI port and the computer has a DVI port, you can use that as well. You don't have to use HDMI to get a digital hi-res image to the screen.