More is better I always say and the specs that were listed on the link are strong enough for very high end work.
Honestly, depending on what type of camera gear, format and type of video work you'll be doing, you don't need all of that horsepower. Anything over 2.0 ghz with a decent V-card and 1.5 gig of ram will work. Just make sure there is a lot of HD space available.
But as I already mentioned, if you can afford it, buy the best system you can get. ;-)
RAM