Since the "full graphics support" element is gaining popularity, I thought it might be worth starting a thread on it. I'm trying to make this a list of everything that could be useful when creating top-down graphics for DF... bear with me . Elements not necessarily presented in order of importance.

-A separate tile for every possible object/creature.

-Gfx Categories. If there's no icon defined for a specific object, the game checks if an icon has been defined for the category it belongs to. As a bonus, nested categories would be great:
Detritus->Body Part->Leg->Dwarf leg
Weapon->sword->shortsword

-Colouring tiles. The already implemented feature allows us to take the grayscale sword icon and colour it according to the material it was made of. Bonus points if the whole RGB scale can be used, instead of just the few colours in the init tile.

-Expanding the principle of varied_ground_tiles to all other graphics- allow assigning multiple images for one object/ type of rock/ creature etc. (chosen randomly).

-The possibility to define dedicated graphics for workshops would be great.

-A simultaneous display of an object and the tile it is standing on (a dwarf on grass, a cabinet on a stone floor).

-A graphical representation of slopes using a set of simple gradient icons (I've already created those) superimposed on the basic ground tile. As seen on this picture. It would be most excellent if ramps were limited to these 12 tiles for easier visualization and less confusion (and more control).
 
-With the above feature- simultaneous view of a few z-levels. Lower levels could be depicted with lower colour intensity and contrast. A simple "shadow" around the edges would help distinguish the layers.  (as seen on this pic- though it doesn't show the proposed ramp display.)

-Also on that picture- a "surface view", in which you get to see ALL surface terrain layers at once and all units aboveground (ie. objects and terrain higher than the active layer are also shown). In this view, the cursor is presumed to be pointing at the surface- if you want to point at something in the air or underground, you use the normal DF layer display.

-Tiles made of multiple separate images- mainly for walls. Like an image of ore veins over a basic rock wall tile. With a good blending method, this would also make engravings look much better.

-Different tilesets for different zoom levels (supposedly very easy to do). This way, when zooming in, simple graphical symbols could be replaced with detailed images.

-one creature per tile. The current situation is as much a display problem as an unfortunate gameplay mechanic. Multiple creatures loitering in one tile prevent you from admiring the large population, take away the challenge of having to design large enough spaces (mostly meeting rooms, but there's much more to it), and most of all make combat completely unreadable. Therefore I suggest that two creatures should occupy one tile only when one is squeezing past the other, unless they are somehow FORCED to occupy one tile like animals dropped into a one-tile pit (and it that case, should more space be freed, the squashed animals should "spill" to the neighbour tile).

-better combat display: the current "purple background" that means the unit is engaged in melee isn't very informative, especially since in a larger group you don't know who's attacking who. Once the display is freed from the stiff tile system (and I DO mean the display, not the gameplay), something like this would be extremely welcome.

Finally, once there's nothing better to do: some sort of an optional orthographic projection. In order to make this usable without having to do graphics for everything, I present: ascIIIso. Everything but the basic wall cube, ramps and stairs is the default curses font! (automatically edited).