I have had my current Dell XPS for about 4 years and I’m on my third video card through failures and it appears to be acting up again, but now my warranty has run out.  Plus my PC is just not powerful enough for proper editing of video.  It stutters aong when trying to render or scrub.  So the search is on for a powerful PC to edit video and hopefully everything else will be looked after if I go for that.  I use Adobe Premiere Pro and After Effects and the big thing in CS5 was the introduction of the Mercury Playback Engine which uses the Cuda architecture of the Nvidia cards to give smooth real time playback and rendering even with complex effects applied to many video tracks.  I’ve selected Dell machines for many years but I got advice to look at the HP workstations, in particular the Z series.  After looking at some sites that provide turnkey solutions it also appeared that the HP workstations, the Z400 in particular, form the key component of the system usually with the Nvidia FX3800.  When it comes to the graphic card though I am inclined to go for the newer and more highly specified Nvidia Quadro 4000 which is only a little more expensive. I am told it is really more for 3D work so I think I will get the rendering and smooth playback I’m looking for but also better productivity with After Effects.  Finally I need to decide on the harddrive.  With a good workstation with Xeon processors and enough RAM and a good graphics card the speed of the harddrive can become the bottleneck.  Most turnkey solutions appear to favour a Raid 0 set up, but I’ve been warned that this could be problematic. So I’ve now narrowed it down to either: SAS drives, an SSD drive or a 10,000 rpm SATA drive.  There’s not much in price between the SAS and the SSD solution (once you take into account you have to buy a SAS controller as well), although I can probably get more space with SAS.  At the moment I’m inclined towards SSD, but I need to do a bit more research.  So hopefully very soon I’ll have my new workstation.