The new task manager is nice? Are you kidding? There have to be close to 50 processes running on the machine, so why does it show a blank window in its default view? Terrible. In its more functional views, it wastes desktop real estate with that tons-of-white-space-and-large-font trend that's infecting everything.
The new task manager is loads better than the old one. It clearly distinguishes between windowed apps and background processes, shows more stats by default (in "More details" mode), has much better startup modification abilities, uses color to show resource usage, etc. etc. I welcome the whitespace, as it makes it easier to read the data. These days, with higher resolution monitors, space isn't as much as a premium as it was when the XP task manager (which is largely unchanged in 7) was made.
Also, its default view isn't a "blank window". It's a list of windowed applications, which is probably the most important data for the average user. For those who want/need more information, clicking "More details" is trivial, and it remembers your preference for next time.