StarCraft was the first blizzard game I ever played, and I played it for years. this is one of my favorite Strategy games of all time.
Warcraft is also one of the best strategy games, it has been around for a long time, and with good reason.
Diablo is my favorite computer game of all time I think. I love the concept and the way you can build your characters up the way you want, if you havent played it, i suggest you try to, asap.