AGE: 53
OCCUPATION: Microsoft CEO
PREVIOUS APPEARANCES ON THE TIME 100: 1
PRO: The forthcoming release of Windows 7 — Microsoft's first operating system since the tepidly received Vista — could go a long way toward restoring customer goodwill and investor confidence.
CON: The 5,000 layoffs in January — the first in the company's 34-year history — were an eye opener. And Ballmer has already predicted that sales and profits will take a hit this year.