I have plans to improve my ripping workstation, but currently I have a 2.5 gig processor with 1 gig of ram running flexi. I output 100mg files quite often. It takes a little time, but nothing unreasonable. If you are getting a new machine though... go whole hog & put in 2 gigs ram & some serious processor. Otherwise, maybe just add ram to your current machine.
Or do both, & keep the old machine (with more ram) as a dedicated ripping/printing workstation & you can use the new one for a design station, so you don't need to "compute" on the maching that is busy sending large format prints.