BEST PC SET-UP FOR COPYING DVDS?

I need to upgrade my PC anyway... But i'd like to rip and encode (i.e. copy) dvds (films).
What is the best hardware for this? Not the fastest but the best suited - Athlon or Pentium and what speed roughly? And how much RAM is good?
I've heard that it takes several hours to encode a DVD? Or maybe there have been improvements in software/hardware since that estimate. Anyway...enough rambling - look forward to some advice. Thanks!