I've only lost hard once... was roughly $10k in a night on blackjack. In a single hand, I've lost around $2500ish and probably around that in a progressive build up on craps - but I wasn't down after that crap out
I'm up overall with gambling, if you don't count slot machines and sport bets.
Biggest single bet win I've ever seen was $11k. A guy had covered #8 on roulette. It was his last bit of money, roughly $300 bucks - he had spent everything else, that night. It was crazy, the guy was shaking so bad he could hardly have a smoke....