I cashed out $9800USD the week before Netteller closed its doors to Canadians from FullTilt.
I won 530 dollar ticket from 70FPP on PokerStars
and sold the $W for $466.40. So that would be my largest win on Stars.
I won a little more than $1700 on Pokerroom a couple of years ago ago, but I blew that all away in a week playing way too high in cash games so I really have nothing to show for that.