If you're going to buy/build a new machine, load it up with as much RAM as you can afford - at least 512Mb. Another way to cut render times is to get a mobo with a built in RAID controller and set up your HD's in a RAID 0 configuration. This will lower your disk read/write time (a huge factor when rendering large images). Abit KT7a is a good choice (I have 3 I use for render machines)