I started with the Mentzer '83 "Red Box", but had/gotten a copy of the Cook/Marsh '81 Expert rules before the "Blue Box" Expert came out...which I then got anyway...
...cuz, you know,...had to get/have the matching sets.
Moldvay. Picked up at a garage sale. My parents didn't actually allow me to play it for another 10 years (because Satanic Panic), but when I did, it was amazing!
'83 Red Box on my 13th birthday. Ahhh... good times. Ended up taking the D&D stuff up to my cousin's that summer as I was staying with them for a month. We had all of the ridiculous, stupid, definitely-getting-the-rules-wrong adventures that you can imagine a group of kids would have, and everyone loved every minute of it!
At one point my aunt demanded that we spend some time outdoors and banned us from the house - so we dragged the table and chairs into the backyard and played outside!
Come to think on it - That was also when I learned that a DM can never have too many dice. At the time I had only the one set that came with the red box, shared among 7 players.
The first one I used to play was the Moldvay set. That was the one my friend's brother who was my first DM owned and the first one I read cover to cover to figure out how to play the game. When my mom picked up a basic set for either my birthday or Christmas (I can't remember) it was the Metzner set.
Blue Moldvay, same as beancounter (reminds me I gotta do my taxes!). Bought it at a local hobby shop right in the middle of the Satanic Panic. My parents weren't religious, though, so they thought that whole kerfuffle was hilarious.
1981 Basic set. I still have it (and the yellow crayon ) in my closet. We were an all teenaged girl group. Unfortunately, high school graduation sent us in different directions.