There's lots of vbulletins out there, but I honestly doubt if you asked you'd get a response from people. The responses here are almost exclusively limited to the boards about the various games though with that said there isn't much room on the board to go outside said topics here. With niche content comes an unresponsive community about other matters and a woefully inactive one, in number this board has a decent amount of members, but it hits well below it's weight class in terms of discussion and activity not that it's a problem for such a board just something to ponder, but that brings me to my point, it's highly doubtful that the majority of people care one way or another. Leaving it as is leaves it as a generic board and it'll continue as it has, changing the theme won't change much if anything. Only 2 people have bothered to say anything about it at all, with that said and I mean no offense theme-wise it seems as if it's the straight default. In terms of the board it serves what it serves, but there is nothing outside that to actually encourage members to be active here, as I mentioned people's posts are almost exclusively concerned with getting help or information and there are few and far between of people actually trying to help, the members themselves have expressed that nobody is really interested in helping and I largely contribute that to the forum itself, it's an information dump it's not really a community. Cosmetics are simply cosmetic, the white theme is rather straining on my eyes personally. Something close to what Nutaku uses would be safe considering most if not all of the people here use that site anyway there shouldn't be any troubles with using a dark blue theme.

No need to download a theme or anything just change up the style variables.
http://www.vbulletin.com/forum/stylevars