Dual video cards are a waste of money. PR can only use one, SLI is not supported.
SSD? Yes if you have money to burn, no if you are on a budget.
Drobo is OK for backup, but is much too slow for editing, What will you use for editing?
Yeah as Harm said you won't gain anything in PR from running Dual Video cards, SLI and Phsy-x are for gaming only so they are useless for you.
Also, when you go to build out, take a look at ADK. Cyberpowerpc is ok, but it's really geared towards gamers, AKD has better options in terms of harddrive configuration for Premiere.
Thank you guys both for sharing that information.
I thought I would be using a drobo-s on esata or usb3 for editing as well as storage... but sounds like that isn't optimal. Should I just have a second internal data drive to use for editing?
Drobo's run a modified software raid 5 that has allot of overhead especially with the virtual volume. This slows their units down. You are sacrificing some performance for ease of use and features. In backup scenario's it's worth the trade off. However that is not the case for production drives. I would not work off a Drobo at all. Definitely get another internal drive for production instead of the Drobo.
And if you're editing 5D Mark II footage, you will get much better results transcoding the native 4:2:0 5D2 .mov files to 4:2:2 .avi files with Cineform's NeoScene, $99 at VideoGuys.com. That combined with the MPE will give you much smoother playback, plus you'll have more headroom for color grading in post. I know this isn't a hardware response but this utility is an essential part of the 5D2 workflow. Have fun!