3.5 is more internally consistant. The d20 mechanic makes things easier to learn and play, and there's less DM arbitrariness involved.
2e has better balance among the classes. There's no tier nonsense that makes the primary casters practically gods while the fighter is rubbish. Combat's also faster because there's less grid reliance, and hp totals tend to be lower.
Rules lawyers certainly existed back in 2e, and sometimes things could honestly be worse with the way the rules could be vague and arbitrary. And house rules seemed to be the norm with 2e as well. There were plenty of optional rules the DMs could us or ignore as they saw fit, then start throwing in splats and/or Player's Option and you've got stuff that overlaps but is inconsistant because 2e's overall design was a mess.
I'm with Stormonu on one point -- the charop boards really perverted 3e's customization options into a hideous orgy of min-maxing. I liked the basic idea behind these option as it was intended to allow lots of different types of builds, but the idea thast some builds are simply inferior and only some options are worth taking nauseates me.
Sigh, totally did not notice the threadomancy on this thread. Until the sixth page when I realized I was reading my own posts.

Oops.
Heeeheee.
I still stand by what I said earlier though. 3e is a massive change from 2e. The tone of the game is completely different, and I really don't understand how anyone can say you can make easy translations between 2e and 3e. The characters got scaled WAYYYY back in relation to the monsters. The classes are very, very different than their 2e counterparts and the approach to the game is completely different.
I played through a good deal of 2e, and went right to 3e when it was released. And while 3e had some pretty sharp differences, a lot of those differences were a sort of natural evolution of 2e. So moving up to 3e wasn't that difficult.
The classes have varying amount of differences IME. Take a look at the classic 4 classes from most to least changed:
Rogue had the biggest change from thief, so much so the class got a name change! The class went from having a bunch of various thief abilties to becoming the party skill specialist. I think the rogue is better than the thief; the skill focus allows more class customization, and the rules for Sneak Attack were better described than the old Backstab ability.
Cleric went back to having a defined spell list and spheres were simplified into domains. The cleric also picked up the spontaneous casting ability. The real difference comes from the spell list, a few spells were added that made the cleric very powerful. The designers were trying to eliminate the cleric as the class everyone wants in the party for healing, but no one wants to play. They succeeded alright -- by unleashing CoDzilla upon us all.
Fighter isn't too different. The main difference is that the fighter became the party combat feat specialist, which kind of greatly expanded on the various sorts of specializations the fighter could take from the Fighter's Handbook or Combat and Tactics in 2e. This did boost the fighter in comparison to the 2e fighter; unfortunately, the casters got even more boosts to the point where the poor fighter is seen as worthless.
Wizard's mostly identical between the two editions. 3e pretty much folds the mage and specialists into a single class, which 2e had already been doing for a while. Main difference is that the 3e wizard doesn't need spells for familiars or metamagic, and gets feat focuses on item creation and metamagic which really isn't much. The 3e wizard can start scribing scrolls at level 1 unlike his 2e counterpart, but unlike the 2e wizard, might not be able to make any sort of magic item depending on his feats (of course that assumes the 2e DM isn't being a hardass about item creation to begin with, given how undefined those rules were in 2e). The 3e wizard has less restraints on spellcasting though, which can make him pretty powerful. The 3e's best spells are different too depending on the situation: straight up damage spells are worth less because of damage caps and higher monster hp, while crowd control and buff eventually become more valued.