Looks good, though I suggest a different power supply:
If you're on a budget: here
If you absolutely can't sleep unless you have way too much capacity: here
The power supply you selected is /okay/, though the quality of the power it provides is dirtier compared to the ones above. The two power supplies linked above are slightly more efficient as well, meaning more power goes into your computer and less gets wasted as heat.
As far as power budget goes, your system configuration will probably not go above 300W at full-tilt, leaving plenty of headroom for a graphics card, even with the cheaper 620W power supply.