Not me. The new start menu is much more efficient. After using Vista since February 2007, and now Windows 7 RTM since early August 2009, I actually beat up one of my old XP machines one time while trying to negotiate the cascading menu system again. I should note though, that I was having a really crappy afternoon and was getting rid of the system in a few days anyway. My friends got a kick out of the dents in the side panels though .
Nope. I love the new task bar. The Aero-peek is great. Also, the show/hide desktop option being all the way on the right is great. No more right-clicking on the taskbar to show/hide the desktop. Just hover over the button and it will preview what your desktop looks like with/without the windows (depending on whether they are already hidden or showing).
Aeroshake is awesome as well. This isn't the taskbar, but grab a window and shake it. All other windows get minimized. Shake the window again, and all the other windows are put back into the position they were at.
Nope. Aeroshake, aeropeek and the new taskbar make me pine for them when I'm on my laptop at work because we're still running XP.