2-0 away to Ross County in 05/06, one of my most enjoyable days as a Saints fan. A big group of us up, everyone happy, a win that more or less assured to everyone that we had what it took to be champions, then the bus driver informed us that he hadn't had his alloted break so had to stay in the mallard for another two hours post match. Happy, happy day.
That 3-2 win against Motherwell.
The 2-1 at Somerset, 2-1 at Starks from the 2000 season.
The 2-0 win away at Falkirk to keep us up in 2009. Probably the best single performance I've seen from a St Mirren side. Absolutely everything clicked into place that day. Every loose ball was ours, the football was intense, precise and purposeful. We could have walked away with 8-0 that day and it wouldn't have flattered us, we were that good.
It's amazing how away days seem to stick more than home games. The 4-0 against Celtic was certainly a contender though. As was Xmas eve against Rangers.