In 2nd edition you could use miniatures if you wanted, but it is not really necessary. I guess the same thing will happen with 3rd edition, but it's my guess.
I tend to like using miniatures when playing out combats, as it makes it easier to the players and GM to know what is going on without losing much time, but that's a personal preference as I like a lot tactical games. On the other hand, there are people that prefer more "narrative" combats, but then they usually prefer other type of rules, so that's why I think that the 3rd edition will leave miniatures as optional, but will also probably have as main rules using them.
Also, I love maps, specially the beautiful ones you usually get in RPG products. I actually think the main reason D&D is business leader is because of their adventures and maps (which I have used once and again in my WFRP campaigns) because the rules of D&D are, in my opinion, mediocre.
And, sorry now for disgressing, at the moment, a friend of mine is GMing a D&D 4th edition campaign (with a lot of house rules) in our club and we are using an LCD screen. He creates the maps using Photoshop and then he uses Maptool in a laptop to send the maps to the LCD screen. We place miniatures on top of the screen. The results are amazing and, thanks to fog of war, we can automatically take into account things like light, hidden enemies and other stuff that are difficult to keep track of. He once ran an scenario through the warrens of Kruthik (an Alien-like monster) and it really felt like the movie... we never knew where the Kruthiks would hit us next... it was a great experience.
Anyway, the system adds a lot of extra tactical component and even storytelling components to our games. The main problem I see is that my friend needs a lot of time to prepare the maps, but with time we'll have a big collection of maps that we'll be able to use for our adventures (he already has a big one). Also, sometimes the maps get too much attention over the story, but usually that's not the case.