Here is my latest tower.
It's a 194 meter high office tower.
I made this with Google Sketch Up, and rendered it with Kerkythea 2007
Please tell me what you think!

1.
http://img129.imageshack.us/img129/9729/toren1mk9.jpg
2.
http://img394.imageshack.us/img394/3033/toren4do8.jpg
3.
http://img129.imageshack.us/img129/9480/toren5im6.jpg
4.
http://img129.imageshack.us/img129/7051/toren6zo8.jpg

i dont like render 1 and 2 :p
these lines are broken Oo
but the concept is good
the only bad things:
-the black roofs
-the highest roof(doesnt fit to the rest)

Nice. :)
I like your final render best.
Im thinking maby the facade should be more reflective and/or transparent.