Personally, I am a little curious about the RevoDrive and the benefit it has over SATAII and III models. I would like to see a side-by-side windoze load time comparison. I will keep this difficulty in mind next time I go around suggesting rigs to people. Judging by your difficulties, I agree that it would take a very experienced and/or inhumanly patient builder to make them reasonable.
I am so glad that things worked out for you alright. Hopefully the performance of the new rig will help offset regret about the initial difficulties. It is rare for a build to be such a nightmare, and I'm terribly sorry at how much of a pain it was.
About the graphics cards. I'm still pretty sure that there's a way to run them together using the GTS as a PhysX card. However, the question is whether or not you would see a difference in performance, as noted before. If you really want to keep that card and make it work, there are some hacks out there to get the drivers to cooperate, but it might be another painful experience (although probably not nearly as much as the RevoDrive problem). If you bought from NewEgg, you can return for whatever reason you'd like. Newegg is famous for its service and RMA's.
A 650W PSU should work for crossfire. I'm not entirely certain with the HD 5870, as it may have higher power requirements, but I think 600W is the minimum for a crossfire system. The question in my book is whether you have enough PCI-E connectors.
If you downloaded the newest drivers for the HD 5870 from AMD's website (It should be v10.11, I think) then don't download the drivers on the supplied CD. The exception would be if the CD has some special software not available from the AMD site. Here's a link to the software suite: ATI Radeon
The HydraVision and AVIVO packages are in the optional downloads if you want them.
My suggestion for browser is Google Chrome. Not to start an argument here, but in my experience it's the cleanest, has the least bloatware, is the most convenient, and has the largest viewing panel w/o any toolbars.
Go here for the latest BIOS updates and other free software provided by ASUS: ASUSTeK Computer Inc.
they have some nifty stuff there
-Just a heads-up, I wouldn't update the BIOS unless you really want/need to. If you don't care, don't do it, 'cause it's a risky procedure. Any interruption or random data corruption could cause some serious errors.
I'm terribly sorry about the difficulties that I may have inadvertently caused, and for any walls that may be damaged as a result of your resulting frustration. I hope that the help I provided was not totally outweighed by the issues.
And congrats that it's (almost) over!
If you have any other issues later on, feel free to ask for help. My first build went spectacularly, but my issues were mostly after I had it up and running. They were all relatively minor, but they seemed intimidating at the time.