Combat Terrain
When I think about the majority of my D&D career, most combats have taken place in dungeons: ten foot wide corridors leading into 30 foot square rooms (at best!). Manuevering and actual terrain features have rarely featured.
Every so often, we'd get into a ballroom (see Whispers of the Vampire's Blade), and we'll have the swashbuckler climbing down the curtains and swinging from the chandeliers, that sort of thing. (And the wizard hiding in a corner wondering what all the fuss was about).
Most of these experiences were without miniatures, as well. On occasion we'd use them - but mostly just to show party order. About a year ago, a friend of mine bought me an erasable battlemat. This allowed me to represent the rooms much easier. Then Wizards brought out the Fantastic Locations maps.
It has been my experience that my players (and I regularly see about 15 in three separate games) greatly prefer the use of miniatures and the battlemat; and they're also very enthusiastic about the Fantastic Locations maps. (I've been reusing them without any trouble).
From my point of view as the DM, having larger spaces that combat takes place in means the monsters are more interesting with their manuevers. It also has emphasised the effect of speed: the dwarves and heavy armour fighters actually notice the drawback of having a 20 foot speed.
The comment from one of my players last night was that the maps sped up the combats. Personally, I think they take about as much time as normal (which, for my groups, isn't long in any case). However, that perception probably shouldn't be dismissed out of hand.
I've really begun to hate 5 foot wide corridors with a passion. (Why does Dungeon Magazine persist in using them? They are Not Fun in groups of 5+ PCs.) I enjoy having multiple corridors intersect at a location - lots of avenues for monsters to approach, to escape down, and to thus split up the party.
Of course, D&D Minis mean I finally have enough minis to represent things (even if I still proxy them!)
Last night, I ran two contrasting combats. One was a group of 9 fire beetles approaching the party along a 10' wide corridor. As one might expect, it was dull - only two of the PCs could engage, only two of the beetles could attack. The other was a group of 9 goblins in a large cavern with chasms, difficult terrain, and multiple corridors leading to and from the area. The PCs were torn between chasing the goblins and splitting up the party (for the goblins had gone down different places), or staying together and letting some escape. More interest for my players and me.
I still don't use miniatures in every fight. Sometimes I'm lazy, sometimes there isn't enough space for the battlemat, and sometimes the combat is so trivial it isn't worth it. However, I'm feeling that, more and more, I should be using minis and more interesting terrain.