I am also using the latest (Winter 09 I think) release. A couple of simple suggestions.
1.. Don't use Vista!
2.. Always work with files locally then copy them back to the server.
We use CVS, so I check-out my design files from the server and work locally. My machine is a Pentium 4 3GHz with 1.25gb RAM, ATI Radeon 9800XT video (so I can't use 3D).
This configuration actually works pretty well until I get to things like auto-routing 16 layer boards, or cross probing boards with 2000-3000 components.
John