graphic card for 24" monitor

[start2012]

Hi, I recenly upgraded my old CRT monitor to a 24" Dell. Not satisfied with graphic output from onboard graphics. my present config:

Intel DG31PR
Dual core 2.5
2Gig RAM
24" LCD
400Watt power output from PSU

Please suggest a graphics card, looking to watch HD content and some casual gaming.

Thanks

[BpnV]

I think that the "ATI Radeon HD 5770" will be a better choice in this case but then if you want some more option then you can check out 4850 or 4870 as well.