I'll address them as I played them-
2nd ed
Its where it all started for me (Sept 1989) My first character didn't even get finished when he became a ghoul and my own party was forced to killl me.

My first DM experience as I ran Darksun for three years.
2nd ed Player Options Rules
Enjoyed thourghly though several players characters all seemed the same.
1st ed
More than anyhing else- I will remember this edition for the freindships I started and still maintain.
Homebrews that mixed / matched 1st and 2nd
Worked well. Had a good time here also.
3rd ed
Moved our 1st ed game into third. I found new awe and wonder within the game once more.
3.5 ed
EBERRON!!!!!!!! In case you didn't notice.... I like EBERRON!!!!!!!
4e
Hoping to finally try it out this November at Carnage in the Mountains gamecon in Vermont
3.75 aka Pathfinder
I like the new revisions of the familiar.
Like some folks have already said- Love that DnD.