Lately, I've been trying for a Space win, but I always seem to mess up and accidentally win by culture (100k; though both times my culture has actually been at 150k, and I just got too far ahead of the leading AI)
I suspect this is because I'm playing Regent on a Huge Pangea map, so its easy to have 20 + cities at 5000 culture ....
Oh, well. time to bump up the difficulty level, I guess.