I am going to say 6 or 7 at MLG - first one was against St. L is probably 1984 or 1985 - Leafs won something like 6-4. I also saw Gretzky and Oilers at MLG the season after that I believe, anyways...Oilers thumped the Leafs bad! I also say Montreal at MLG (Leafs won, and got to watch warmups at the glass/front row), NY Islanders, Hartford, Buffalo, and St. Louis again. Maybe more - once I hit 19/20 years old, I tried to get to one game a year (born in 1973). Aside from the Oilers game I think the Leafs won every other one. I think one time a few buddies and me drove from Windsor and grabbed scalper tickets for 1 game (Friday night home game I think?).
ACC - first game was Pittsburgh with Kovalev - he sniped one with a wicked wrister. Caught a home opener against Ottawa - watching the 48th Highlanders live is awesome.
Also saw the play Edmonton (lost I think). Saw them lose 4-1 to Colorado as part of my honeymoon (wife is Leafs fan too), later that year Wellwood got 3G and they beat the NYR 9-3, and this is the last Leafs game I have been to. Too expensive, and add in driving 4 hrs from Windsor, plus hotel, food, etc.
Other venues:
Saw the Leafs win their 10th in a row to start the 1993-94 season in Chicago at the old Chicago Stadium (it's final season). That experience was amazing - the fans, you could see the pipe organs pipe opening/closing in the ceiling - still have a "Remember The Roar" t-shirt around somewhere.
Joe Louis Arena - saw many pre-season and regular season games there - my Dad's company had a suite, so he got tickets for the Leafs whenever he could. I actually had a buddy offer me a free ticket to the game at Michigan Stadium (Outdoor classic), but I had to pass as I had a bad pinch in my neck - could not turn my head and was in too much pain, plus the snow was crazy and it was super cold. Also, have played a few games of pickup on the JLA ice - that was cool. Have yet to check out Little Ceasar's Arena.
Buffalo - Head up with some friends to see the Leafs actually win in Buffalo! I believe Mogilny scored the winner - Belfour in net. It was called HSBC Arena at the time - stayed in Niagara Falls overnight.
Montreal - saw 1 game at Bell Centre - some kind of fan bus trip - CuJo in net, Leafs won. My buddy had family in Montreal, so his cousin took as to see a couple things in the city. -4°C in Montreal is a lot colder feeling than -4 in Windsor!
Carolina - My friend and I drove the 14 hrs to Raleigh to see Game 5 of the conference finals in 2002 - Leafs won 1-0. After the series was tied at 1-1 - I hopped on TicketMaster and got tickets for $40, and reserved a Red Roof Inn a few minutes from the arena for $40 - what a crazy experience - Leafs fans everywhere - tailgating in the heat - beer flowing - road hockey games in the parking lot - there was a group who made a leaf out of empty beer cans in the parking lot that must have been 10ft across! There was crazy going down pre-game! It was Saturday night - woke up the next morning and made it back for my Sunday night pickup hockey.
Want to get to Columbus one day, and Pittsburgh - they aren't that far a drive from Windsor. Plus of course plan to check out the new arena in Detroit.