|Fingers suggestion to build a modern system would be the best way to go, but if you can't afford it, you can make do with the Pentium dual core. Just make sure you choose an board that's overclockable; then you can reclock the E5400 from 2.7GHz (13.5 x 200MHz @ 800MHz) to something like 3.0GHz (7.5 x 400MHz @ 1600MHz FSB). That's just a minor overall increase of 300MHz but the FSB speed will be doubled.|
If you're going to install a video card, you don't necessarily need a motherboard with integrated graphics. If that's the case, you should consider a board based on the Intel P43 or P45. And just so you know, 2GB RAM isn't enough for decent gaming. 4GB is the minimum but it would be better to have a 64-bit version of Windows & 8GB RAM.
I can't pick a board for you, you're going to have to do some research. Gigabyte lists 26 boards based on the P45 & 13 based on the P43, but not all support DDR3 memory.
If you prefer Asus, ASRock, Biostar, MSI, etc, you'll have to check their websites to see what they have to offer. Once you come up with a few boards that interest you, search for some reviews to see if they have any issues. Then you'll have to see if anyone still has them available.