depends a lot on your budget..
easiest thing to do would be to encode to either mp4 h264, wmvhd, divx, qt and then edit from there unless using specialized softwares with their own editing format. You lose some of the quality depending on the compression but makes the files more manageable on older machines.
I had to overclock my desktop up to 3.6Ghz from 1.8Ghz for bearable encoding and rendering times but definitely a huge improvement to previous "leave overnight" method.