I met Crompsin via OKCupid. I sent him a message (high match percentage, whee!), he replied with "You live too far away," and we just started talking via AIM with no real intention of meeting each other. That lasted a little over a month before I decided to drive down to meet him over New Year's Eve.. and if you read his journal you know how that went.
I've also met a couple of losers/creeps/weirdos, as a few people I talked to online for a couple of months as friends. Met a couple in real life, but not very seriously.
My current relationship is the only one to ever come out of meeting someone via online personals. The same is not true for him, though.