Unfortunately, I don't like it. Not because its new, but because I don't like "position:fixed" elements when I scroll. I am using a netbook most of the time and all these fixed elements take up half of my screen (maybe not half, but feels like it). When I scroll, I do it because I want to scroll, not because I want most of the GUI to not move. Unfortunately, position:fixed seems to be the current "thing" to do for many designers :(
This part hasn't changed in the new visual design, but duly noted. Note you can changed the fixed header in the settings as well as turn off the sidebar.
Going to throw my vote in here as well. I hate position:fixed and am constantly writing CSS hacks to remove these elements on pages. It's a trend I don't like, and yet it's becoming very common. I'm just a grumpy person that hates change, though.
