To start with you need to get the fastest processor you can afford, but I would recommend not getting the newest/fastest as these are too expensive and will drop in price in next to no time
Go for 512Mb RAM or more if the budget stretches that far. Obviously go for a large separate hard disk for video capture.
DVD writers do seam to be the way to go, but which format? It may be more expensive but the Sony multi format drive will make sure you don't end up investing in todays version of a Betamax VCR.
Just be aware that no matter how fast the proccessor or how much RAM you have rendering will still take hours. Hardware CODECs on dedicated capture devices are the only real way to speed things up by a large amount.
Mark.