It doesn't really matter what Editor you use, they will all encode AVI video to around 4 minutes per Gb.
As for the MPEG quality what setting did you use? For best quality set the compression rate to 8000Kbps (variable).
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.