I personally like the Corsair but it cost more. The problem with the Antec is that it is oversized. If you can fit the Antec and want to save $20 go for it. If you want to have an easier time fitting it in and what I would consider a slightly better psu go with the Corsair.
A note on your setup, be sure to get the 955 with the c3 stepping because it overclocks better and produces a little less heat. I have heard that the heat sinks that come with the 955 are a bit loud and overall not that great, so pick up a good heatsink.
The 955 with c3 stepping has a M instead of an I in the Model #