I've been using an X3440 for quite some time now. I got it because, at it's price point, it was a no-brainer. As Cyberbeing said, performance wise it falls somewhere between an i5-750 and an i7-860. My chip has overclocked very well, too.
As for gaming and hd encoding/decoding, you'll be just fine, although your gaming will more heavily depend on the GPU you're using.
Indeed there aren't what i'm saying is that due to the price differential between 4GB and 8GB modules while (according to supermicro) you can go 32GB with a LGA1156 xeon and 4x8GB modules a dual socket LGA1366 system with 8x4GB modules is likely to have greater total processing power for a comparable total cost (you will spend more on the CPU(s) and motherboard but less on the ram) and will have room left to expand.