I'd probably get a new psu. I would look at Seasonics though, instead of Rosewill. I just like Seasonic in general, but Rosewill should be a good choice too. Don't want anything happening with a bad psu because you got a better case :P That said, cooling is a pretty high priority of mine.
I would get the black case. It lookes awesome and the current case looks a bit cramped. I chuckled when I saw the little fan on the GPU. What is the little card in the 2nd to last picture
I've got my faith in Rosewill, they have basically super flower PSUs in them and I've used around 60 of them personally, Rosewill does make some Shitty PSUs but this is not one of them
Ah okay. I have a Raspberry Pi in an SSH config and it is absolutely amazing. It looks like the beagleboard can hook up to the RPi via the GPIO pins(I assume that those black bars on the side are GPIO pins. Not up-to-date on all the credit-card computers)
Wait for the second version of the BBB, I got one and its still flaky sometimes.
There are faster open source alternatives, the most price/performance efficient ones are the one based on the Rockchip RK3066 dual core, and there is even a quad core Rockchip based devboard. Problem is that they don't have the same community support as the BB. I would stick with ti, the amount of community developed out-of-the-box stuff is amazing, and you can get a lot of inexpensive expansions later that just work. But wait for the second gen BBB's, they will come in at most a couple of months.