Awesome RAM and MOBO and they are compatible, just make sure to turn up the voltage and set the timings in BIOS manually, its easy and will run without having to do it. Also make sure to update to newest BIOS version, F6.
That GPU is a great choice, don't listen to all the nonsense about waiting for GPU that will be more than adequate for awhile, there will be a DX10 update for all GPU's and there won't be support problems with VISTA Microsoft is not stupid enough to make an operating system where everyone will have to update immediately to see adequate performance, there is a lot of hype at the moment as with any software change, especially OS's.