I'd go for the 690 personally - mainly because if you ever wanted to water cool i think its the better alternative. I think the 690 is a bit bigger has good cable management and looks really smart, eSata on the front I/O panel as well. There actaully isnt alot to choose between the two i dont think unless you want to water cool. It has a sort of reserved yet solid look to it i reckon. Also, why not give the 690 a try if you already have an Antec 300 - at least then you'll know No brainer for me though - Coolermaster 690.
If you have the space I would recommend a Gigabyte 3d Aurora 570 you can pick it up from eclipse computers for 60. But i don't know there reliability as i have never used them before.