hishan i coulnt think of that design to be a tower,cause you will have too much room that will go to a waste.
Not really, that's only the section where the workshops were housed. With a little planning, you could even add another ring around the outside if you needed more room. Each floor contains up to 64 3x3 rooms. You'd need at most 3 levels for dwarf rooms (192 rooms), a floor or two for the nobility (8 rooms per floor), a floor for farms/dining (8 rooms) one floor for workshops (64 rooms) and everything else (storage/stores/etc.) could be placed in whatever remaining z-levels you have. A basic tower to accommodate 200 dwarfs and workshops would only need to be 11 levels (including 4 floors of mineral/object warehousing to separate the living quarters from the workshops.) After that, adding more levels would add more storage and fluff. Ok, maybe make the first 4 levels the barracks, practice areas, trade depot and first defense.... 15 levels. I've been on more than enough maps that are more than 15 levels although you may want to put some of the space below ground. Maybe the workshop, storage and barracks. Then with spare miner time, you can have them dig out a slopped area around the tower for a dramatic touch and a fairly good defensive advantage (have fortifications around the circumference.) Heck, here's a pyramid I started that has at least 10 levels above ground on a flat map:
http://img72.imageshack.us/img72/7393/pyramidqu1.pngIt's situated around a magma pipe in the center of the map and covered with Obsidian ramps:
http://img248.imageshack.us/img248/1074/pyramidundergroundod7.pngI had planned on mining out the ground around the pyramid to reveal it when I was done, but this was another project set aside by other things.