FVWM can do this pretty easily. The real trick is to set your mouse buttons to do such things as lower and raise windows depending on which button you clicked the window border with, that way you can find things which your big, maximized window is probably obscuring.
Tiling WMs also do this, but you will miss a bar at the bottom to help keep track of your virtual desktops and tray buttons and probably your conky output. Find one that let's you hide the bar with a keyboard shortcut so you only have to see it when you want.
Docks want to replace the taskbar, but they're clumsy by design. How do you open more than one program, and then how do you figure out which one it brings to focus when you click on the singular icon? If you could limit every program to 1 and use tabs it would work, but that's a *lot* of policy to make something work the right way.
You might also use any WM that let's you roll up or shade windows, but I can't recommend that too much. Sooner or later you'll overlap the title bars and be totally lost.
I think the taskbar is one of our best metaphors on the desktop. It's not pretty, but it does do a lot of useful stuff that isn't available anywhere else.