as much as i (and probably the majority of the people on here) would be bias towards the e46, i would still go for the e39. my dad use to own an '02 530i w/sport and it was awesome to drive. he now has a '97 e31 840ci and that engine was used in the 5er up until '02 and it is an amazing engine. so that engine minus ~800lbs of weight (8 weighs 4600, 5 is about 3600) equals a dam nice car. make sure it has a 6spd and ///m sport package (try for an '02).
“I’m sorry, but having an Aston Martin DB9 on the drive and not driving it is a bit like having Keira Knightley in your bed and sleeping on the couch. If you’ve got even half a scrotum it’s not going to happen.”