I HAVE NO OTHER CHOICE OK???! JUST ANSWER AND REMLOVE IT FROM THE HOLD
Systems / Network Administrator for 20 years.
Most active voter on all of StackExchange: First person on all of StackExchange to vote on questions and answers
50,000 100,000 times.
Before that: first person on ServerFault to vote 5,000 times and every 1,000-vote milestone after that, first person to vote 19,000 times on a single SE site and every 1,000-vote milestone after that. Currently at 50,000+ votes on ServerFault.
As of August 2015, won't be the most active voter much longer... Gilles has more votes on U&L than I do on SF and is likely to pass me for the most total votes soon. Bastard!
Handy data.SE query that shows the most active voters - thanks @PeterH: