We have several large chessex grid maps and a collection of dry erase markers.
On the fly during the game, I like to draw in an assortment of reasonably well-detailed interior furnishings and garnishings for most every room/area (tables, chairs, bushes, etc), using one or more colored markers, adding more rooms/areas as the group explores further.
The main reason I do this is because I think adding a visual aspect to the game cuts down on the occasional confusion you have when making verbal descriptions about locations and positions.
We occasionally pull out the backup maps when the group moves between levels (or scenes) so that we can go back and reuse a previous area/level map if we need to.
Sometimes, I take a battlemap and predraw a major room/area before the game. For example I prepared a super-detailed/fancy 3-D drawing of the Sea Ghost for the Sinister Secret of Saltmarsh module not too long ago, with grid squares for every deck shown on one map, and some extra artistic flourishes to make the ship look realistic, which really added some fun to the game (and we re-used the ship map for several sessions and battles).
Every player has a miniature to represent his own character, and for a longer campaign they usually pick out and paint some nearly perfect representations to add realism. Most of us have a collection of miniatures, and one player has a humongous collection, so between all of us, we can usually find a monster figure on-the-fly during the game to represent whatever encounter comes along. I've also started the habit of emailing the one player ahead of time to make sure he brings a few key figures (adding a few red herring monster requests to scare the bejeezus out of him
).
We draw out a map and place figures for scenes where combat is likely. Occasionally for things such as a tavern scene, we draw it out and place figures there too (you can artificially create instant tension by setting out the scene in miniatures, because the players automatically go into panic mode LOL). When the group is in a dungeon-type area, we position/move figures around a map almost exclusively. And to be more specific, in the dungeon it's normally not round-by-round figure movement; the players verbally describe what they're doing, and just whip the party figurines around to reflect a major change in position, so that if combat breaks out we have a general sense of where everyone is standing.
We do occasionally use six-sided dice to represent huge crowds of people or monsters. The advantage of using dice is that since we have a wide variety of colors and each die is labeled with numbers/dots, so that way it's possible for us to keep track of the location of specific people/critters if we need to.
It is a problem for the player with the largest miniature collection to carry/lug all that lead weight around, plus books. So he usually only brings two toolboxes full (which I would guess is about 50-75 miniatures of various sizes), and one or two other people will bring maybe a dozen extra figures.
Now, this is not to say that we are totally reliant upon all this map stuff, or that we think it's necessary at all. There are plenty of sessions where we never need to pull any of this visual gear out. In fact, we often do so much interactive/conversational roleplaying that the miniature battles are a rare breed. We're the type of group that can spend a whole night roleplaying out the details of a walking tour and shopping spree around an interesting town full of NPCs (the players verbally roleplaying their scouting of an inn with a room they like, or hunting down the right personal clothing items including the perfect style wolf-fur mittens, etc, LOL). The point is, your group can be the type that puts emphasis on using their imaginations for some things and still resort to miniatures for other situations.
As far as chits/counters go, we've never used them. Sure, they're everywhere now (modules, dragon mag, dungeon mag, claudio pozas cool chits, etc), but they just haven't caught on with our group. I think the reason is probably that the players definately enjoy using miniatures for themselves (because it's fun for them to pick out the perfect one, and to paint it), and if we put a "flat" giant next to a taller 3-D lead/plastic adventurer, it's just won't have the same visual/emotional impact on the players as placing a towering lead figurine of a giant on the table that dwarfs their characters. So basically it's the "flatness" of the chits/counters that turns us off. The players enjoy seeing those bad-ass monster figures looming over their own just as much as the DM, because it's more exciting for them to defeat something that looks so cool and intimidating.
