In the long run, I think beating the Bulls regular season record will have more historical significance than a second Warriors title run.
However, if the Warriors win 73+ games and then fail to win the title, I think it'll be looked at the same way the Pats' 2007 season is looked at. An amazing regular season, but a disappointment because the team fell short of proving they were the best in the league that season in the most important game of the year.
Basically, I think I'd care more about getting the regular season record, but if you fail to win the title after getting that record, it was all a waste.
If the Warriors really want to think about making a mark on history, they should get to thinking about what it would take for them to win 4 titles in a row. A team hasn't done that since before the merger.