The 4th edition D&D rules continue to be a divisive force within the fantasy RPG community, but that doesn't bother me since I wasn't a member of the community when this schism occurred. I like how straightforward the 4e rules play, and appreciate the various elements that have been borrowed from the card game, board game and video game worlds.
Where there used to be a lot more room to 'fudge' things in terms of what monsters were caught within a spell's area of effect, and who could see whom, and how long before a wounded character either died or regained consciousness, the new rules pretty much require a map and either counters or miniatures to insure the tactical situation is relatively clear. Since I still have most of the old Grenadier miniatures and such from when I began playing at age 13, this requirement suits me just fine, and the fact that I picked up an awful lot of figures during my 11 years with Games Workshop means I am pretty well kitted out in this regard.
As a result of this, it's been ages since I have had to use my pencil case full of multi-coloured army men to represent the party's opponents, but back in the day, that worked just fine. ("The green ones are orcs, the grey on is the chieftain, and the two tan ones are bugbears." "I'll take the bug bear throwing the grenade, the wizard can get the one with the rifle...") The bulk of my current foes are drawn from the old Warhammer Quest game produced by GW. If you can find one of these on eBay or at a garage sale, I highly recommend picking it up: over a hundred figures, including a dozen giant rats, bats and spiders that can proxy in for a dizzying array of different dungeon denizens, plus orcs, goblins and skaven (rat men) to round out the medium sized opponents.
There's even three minotaurs to cover the larger, ogre sized creatures, and I painted one up to represent a Bronze Warder from the Thunderspire Labyrinth module. Citadel Colour hasn't made Jade Green in ages, so I had to schmear a few colours together in order to get something approximating verdigris.
We have a few sets of the Wizards of the Coast Dungeon Tiles, which are gorgeous, but more often we use a large vinyl Chessex mat with a 1" grid printed on it (with 1" hexes on the reverse side). This gives us a bit more flexibility for encounters that take place in oddly shaped rooms (which the aforementioned Labyrinth has in quantity), and also lets us use coloured markers to show things like fireplaces, pools, and so on. We have been using Lumocolor non-permanent markers for this, but they are fairly fine tipped which can make it difficult to discern precisely where the walls are.
Another handy item is an assortment of pipe cleaners to show the borders of spell effects, especially those that can be re-directed or which follow a character around.
My favourite though, has to be this Flaming Sphere (which I found on eBay), and I think you will agree it is a much more flavourful way of depicting this spell's effect than a penny, coloured die or a cardboard marker.
There is also a Dungeon Master's set we've been using to show which characters or monsters have been slowed, dazed, bloodied or subjected to ongoing damage.
Previously we had used a small white board to record both initiative order and ongoing effects such as these.
Recently we have been using the Initiative Tracker app by Lvl 99 Games for my iPad instead. It's a bit fancier, not quite as flexible in terms of what it can do compared to a whiteboard, but it does actually move characters from the bottom to the top as they take their actions, which makes it easier to keep track of where you're at in the order even when resolving multiple opportunity attacks and the like. You can colour code each combatant, and there are a variety of icons you can turn on or off to signify bloodied, stunned, etc. And it's free, which is nice, but means we are unlikely to see too many upgrades for it.
Despite the fact that the party is nearing 6th level and none of them have died yet (despite a number of close calls), I can't say enough good things about the dying rules in 4e: once you go to zero hit points, your model is laid down, and on every successive turn, you make a saving throw versus death. On a twenty-sided roll of 10+ you pass, but a 9 or lower means you fail, and your third fail means it's time for you to roll up a new adventurer or for the party to cough up an expensive Raise Dead ritual. This brings a lot of drama to the table, which is much appreciated, at least by this Dungeon Master.
It becomes critical to depict a couple of things on the tabletop as a result of this, the first being how many death saves have been failed, and for this I use an assortment of tombstone figures I have acquired over the years. We've also put big black X's on the whiteboard (three strikes and you're out!), but gravemarkers seem so much more evocative, don't you think?
The other is to differentiate between those models representing a character in mortal peril as opposed to those who have been knocked down, taken cover or are having a nap. I initially used this vintage "Minor Death" figure (Death is scalable? Seems like an absolute to me, but maybe it's like Miracle Max says in The Princess Bride: "Turns out your friend here is only mostly dead..."), and stood him at the head of those who had fallen to zero hp:
|Jim Reaper, Repossessions Dept.|
|Carrion my good fellow, carry on...|
The last couple of tools I use are actually outside the proper rules. I have a small pouch of flat glass stones that I hand out to individual players for various reasons: good role-playing, a hearty battle cry, a devastating pun, or the timely roll of a natural 20 which might turn the tide for our beleaguered heroes, like last night when not one but two dying players rolled 20s, which brought them to their feet and back into the fight.
Once a player has collected 10 of these stones, they can trade them in for a tiny d20. This small dice can be used to re-roll any single roll, or it can also be used in the place of an action point. Best of all, they are transferable, and selfless players have given them to another character in order to get a second chance at a desired result.
That kind of behaviour simply must be encouraged, and 1/10 of a re-roll is a small price to pay.