Not wanting to piss on your ideas but I think a lot of peoples' first instinct is to build high. And then everything kinda ends up looking the same (because there's a limit to how high you can build and also to how far you can differentiate one tower from the others).
I think building sideway, building something large in area rather than height, allows for more expression (and also lends itself to later additional development next time you have an idea).
EDITED: 23 Jun 2011 20:22 by X3N0PH0N