Two things had drawn me to Mahler's 2nd when I was in college: First, I'd see the St. Louis Symphony's recording under Slatkin at the library all the time. The cover was beautiful, and almost celestial. I finally resolved to check it out when I heard an excerpt of the work (Stokowski's LSO/RCA version) in the Carl Sagan show Cosmos. Then I moved to others. I quickly gravitated to the 7th because of its tenor horn part, since the American equivalent is the euphonium, my instrument. Pretty soon, I was trying to belt out the opening bars when warming up in practice. The 9th was always special for me. Although I'm still not a huge fan of the Chicago Symphony Orchestra, I initially liked the Giullini version because of the LP cover.
I despised Karajan's way with Mahler, but it has since grown on me. In fact, I picked up his M6 today on vinyl. We'll see how that one goes.
Bernstein was an early favorite Mahler conductor, but I learned many other great versions down the road.
One of the hardest for me to like was the 3rd, although there were many moments I loved. Lately, I've been thinking it's his greatest work. It's just so unusual. But when I was younger, I found the first movement very hard to take because of those guttural sounds in the low brass.