For me Rossi's most memorable victories were the 2004 ones, first year with Yamaha, the bike was not as good as the Honda, and he still managed to win the championship, that's the first time ever I saw the championship won by a rider without the best equipment. The only time I've admired the guy.
The toilet and Biaggi incicents where funny but I don't care too much about the comedy side, I like bike racing, if I liked comedy I'd watch something else. (That goes for the Actor aka Jorge Lorenzo too)
The Jerez incident with Sete for me was the lowest point of Rossi's career and not memorable at all, just proved to me he has very little ethics, which I do consider important.