Both are TOP ones.
comments: It is sure the Burj Dubai will be the tallest Structure whatever use and type all over the world. That is impressive even with less meter 807,8m instead of more than 1Km high.
I would put the Ostankino tower also in the first one and Petronas to see that CN Tower and Ostankino is even higher the Sears, Taipei 101 and Petronas. It is sure today the highest Human use Structure out deep waters is the CN Tower and Ostankino as 'buildings' before the Sears one. Considering only as building type the Sears is already the tallest. In one year with Burj Dubai all finished the history is complete different, even comparing to Masts and Offshores.
The structure in GUINESS forever of all structure types will be Burj Dubai as direct human and non-human Tower use.