I agree with the deletion of old users. If someone hasn't logged in for a year, I think it's safe to say that they won't be back.
AND WHO CARES ABOUT OUR NUMBERS?!
I think it looks worse to have all the empty usernames than to have a few less members. Plus, David always complains about server space, right? Well, if he's so against custom avatars for this reason, then why would he ever stand for so many useless accounts taking up this precious space? Either A) he's exaggerating/lying about the server space, or B) he just doesn't have the motivation to maintain the forum (i.e. doesn't feel like adding custom avatar support AND doesn't feel like deleting old members). One of his common arguments is that having all these members makes him happy.... What? I mean, yeah, it's his forum to do what he pleases with, but if he wants it to be a GOOD forum, he might consider actually doing some upkeep. That's just my opinion though.
I've always felt this forum to be a little behind others in that it's not professionally maintained. To be honest, it feels like a bunch of kids just threw out a nifty forum with a computer theme and let the member post content support it. That's no way to run a forum. It involves active participation and administration. So yeah, I guess my point is that David should either allow us to have custom avatars (since pretty much the only argument against it is server space), or he should stop complaining about the server space since it obviously isn't an issue considering the number of old accounts.