Yes and No.
Things that are the same for me (all IMO):
1) The strong class and race, spell and magic item archetypes haven't changed.
2) The assumptions about the D&D "default setting" (full of dungeons, thieves' guilds, adventurers, beholders, planes and the strange moral compass known as alignment) remains more or less unchanged, despite tweaks such as opening up racial class restrictions.
3) The magic level of the game hasn't changed, except in terms of perception of it. Most seem to have run 1E and 2E with a lot of gold and magic items, and by opening up magic item creation, 3E just reflects that.
4) The emphasis on the dungeon as the primary adventuring environment, to the exclusion of improving the state of the art of a good model for wilderness or urban adventuring hasn't changed. ("Getting back to the dungeon" aside, an opportunity to improve the game's culture was missed here.)
5) The emphasis on big, campaign modules having to be megadungeons hasn't changed. The megadungeons becoming dull in play after a while ("too much of a good thing") hasn't changed either.
6) 2E's emphasis on "fluff" has been found wanting (and seemingly scapegoated for TSR's commercial failure), and 1E's emphasis on stats embraced...seemingly for both ideological and commercial reasons. The result of the application of such a simplistic rule of thumb across the board isn't always good, but...
7) ...Dungeon magazine still exists, so it effectively doesn't matter what approach other products take. It's easy to ignore books of exceedingly questionable utility full of god stats when you're too busy mining Dungeon for material which you can actually use in a game.
8) Monster Manual II and the Tome of Horrors have arrived/are arriving to save the day with regards to taking the "feel" of the monster palette in the game back to one more reminiscent of past editions.
9) You still get to roll a lot of d20s, and there's still the opportunity to muck around with the other array of polyhedron dice as well.
10) It's still a game based around sitting around a table with some mates (one of who is behind a piece of screen of cardboard) and playing make believe in what is usually a swords and sorcery fantasy setting.
Things that are different for me (again, all IMO):
1) 3E is more inconvenient to run on the fly than prior editions.
2) 3E's combat is more fun due to the range of options opened up in combat.
3) 3E's push towards miniatures grids and reduction of the level of combat abstraction can reduce combat visualisation on a storytelling level, but enhance it on a tactical level.
4) 3E's core Monster Manual selection delivers a different character to the game, which has an inferior flavour to past editions.
5) 3E character creation is more fun than in past editions because it presents more customisation options, and the opportunity for more powergaming fun (I don't see that as a negative, btw).
6) 3E's prestige classes are no better than 2E's kits in terms of being problem-prone, and restrict when a PC can take them regardless of campaign reality.
7) 3E changes the perception of magic through magic item creation such that magic items hold less mystique.
8) Because 3E is made at such a time whereby the hobby has established norms and ideas of what is progressive and what is "done", there's a different kind of pioneering going on, and the products reflect that.
9) Game balance has changed with 3E, in that it exists this time around. Thieves/rogues have caught up with their counterparts.
10) Without practice, character creation and NPC statting is now so intensively time-consuming as to suggest the use of computer programs to speed up the process.
