It generally is more helpful to you if you do this BEFORE you buy it...
How good it is depends on what you paid for it. What was your intended budget?
Just looking at it, you probably overspent on the case compared to the guts. A better case would have been the Antec 300 Illusion for ~1/2 of the cost. That would have allowed you to put a bit more into the actual computer part of the build.
The board is alright, but I think this similiarly priced one would have been better:
ASUS M4A79XTD EVO. It trades the onboard video for extra SATA and USB ports. It's also one of the best budget boards available.
The 620 is a good CPU, but very cheap. This is one part where the expensive case hurt you. If you had gone with a cheaper case, you may have been able to afford a Phenom II X4 955 BE (maybe). Still a good choice though.
The GPU is only a good choice for its price. Don't except it to do much gaming. For $50, it was the best choice, but you could have done better with some cuts elsewhere (again that case).
Depending on the exact sticks, you may have overpaid for the RAM. OCZ makes some fairly expensive sticks, but sometimes have rebates to make them better. I can't determine what the timings are by your description, but I'm hoping they were 7-7-7-x. Overall, not too bad of a choice, especially if you got the $25 rebates on them.
I have no issue with the PSU. OCZ makes great units for cheap.
What HDD did you put in it? Right now, the best choice is the Samsung Spinpoint F3. It's the best HDD available and it's one of the cheapest at $55 for 500 GB ($85 for 1 TB).
Overall, with the exception of the expensive case, it's a decent build. Probably could have done a little bit better on the guts, but se la vie. I'd probably call it a low-budget all purpose machine. It's CPU is a little weak to be doing heavy processing task, and the GPU is too weak to be a gaming machine. It'd be great for someone only interested in doing some general tasks (internet, Word, Excel, non-HD video).