Ah man, the complete books was among my favorite additions to 2E. Though, you did have to be careful with it - especially anything after PHR4 - Complete Wizard.
Complete Fighter was "Wow! This is great!"
Complete Thief was "Interesting - some good stuff here."
Complete Priest was "What the hell?"
The 'Complete' Priest destroyed my faith in the Complete books. Even to my young and not-particularly-aware-of-game-balance mind, I was aware that there was something wrong when the replacement system produced characters that were 99% strictly inferior to the base Cleric.
I loved the idea of the book, sure, but it was done in such a ham-fisted way.
The earliest big campaigns I ran of D&D were AD&D 2E. I'd played and run 1E earlier, but hadn't run big ongoing campaigns. That changed in 1990 when I started University, and I ran campaigns of 2E for the first two years. (After that, I played and ran Amber a lot).
Later on, when I got back to D&D, I ran a very good campaign with the Player's Option books. I loved those books, broken though they could be. I especially loved Combat & Tactics, which prefigured the miniature game that 3E would become.
This year, I've been running AD&D 1E again, and loving it - though there are many, many rough points in the rules, the core is strong and the character options suit our needs. I don't think I'd ever run pure 2E again: it'd have to be a hybrid system, using a lot of the 1E versions of the classes.
Cheers!