It's pretty easy to pick good parts with a budget like you have.
To address Bloodfrost comment, the 1156 platform would be enough for your usage and might cost a little less. The only advantage that the 1366 has it a better CPU upgrade path. The 6 and 8 core CPUs will only be available on the 1366 platform (as of now.) If you're into some serious production editing and graphics, I'd stick with the x58 mobo. But if this isn't pro grade stuff you're doing, the P55 is a viable option.
There are less expensive 1tb HDDs out there with better performance like the spinpoint F3 1tb. But it only comes with a 3yr warranty instead of the 5 like the cav blacks do.
The self contained water kits don't do any better than a good air cooler and usually cost a lot more.
http://www.tomshardware.com/review [...] ,2370.html
I'd shoot for something like this:
http://www.newegg.com/Product/Prod [...] 6835103065
This site is where I do most of my cooling research:
http://www.frostytech.com/top5heat [...] ELHEATSINK
Last note, if you're looking for bang for buck, there should be some crazy deals by the end of Nov, specifically black friday if you can wait.