Video Card help

I recently bought parts:

Gigabyte EP45-UD3P - Motherboard
Intel Core 2 Quad Q9400 - Processor
WD Caviar Blue SATA 320gb @ 7200 RPM - HDD
1 Case Fan, 1 CPU Fan
No memory yet but I'm planning to get something like Kingston 4gb (2gb x2) DDR3, 1800Mhz

Any suggestions for a video card? I'm a heavy gamer, I can stay online for about 8 - 12 hours (with semi-breaks). I currently play World of Warcraft and I want a semi-epic fps. I would also want this video card to last for about 3-4 years. Suggestions please?

The last graphics card I had was GeForce 3xxx something (i forgot) and I am moving on I do not know much about video cards. I do not know stuff about ATI cards so please if you can elaborate on your suggestions, it would be awesome.

oh okay, DDR2 memory then thanks for the heads up.

Also, I'm only using a stock monitor. It ain't HD. Would the ATI HD cards still work as intended? Or they are named HD just because they LOOK better in HD.

"HD" is a term that applies to TVs not monitors. 720p "HD" is 1280x720 and has been pretty standard on monitors for about a decade so if your monitor really isn't "HD" you should definitely upgrade. In any case that's just the name of the card and if your monitor isn't very new/large those cards are probably overkill and much more expensive than you need right now. However, you did ask for something that will be viable for 3-4 years and those are the only cards I would consider recommending for such.
You would probably be better off getting a card appropriate for your current monitor and upgrading it when/if you get a new one so tell us what resolution you plan on using.