I've spent much of today playing with Ubuntu in VirtualBox on my Vista laptop. I got hold of a copy of the iso image for the alternate install of Ubuntu Gutsy, and used this to install a command-line only system in VirtualBox.
From there, I just needed to edit my /etc/apt/sources.list to remove the CD-ROM from my sources, sudo apt-get update and sudo apt-get upgrade to get everything up to date. Then I was free to start tinkering, installing window managers to try them out.
Once you've got your command line install working and up to date, you need to add the xorg package to install the X Window Server. I also installed xdm to let me log in graphically. From there, you can just install the window manager of your choice.
My favourite so far has to be IceWM, which resembles old versions of Windows in appearance, and is fairly simple to configure, although I'd have to stick with it a while to be able to get to use it properly. Technically I'm already using it (my Eee PC uses IceWM for the tabbed interface in normal mode), but I like the possibilities of it.
Enlightenment is, in my opinion, a better window manager and looks nicer, but E17 (the most recent version as used in OpenGEU and gOS)hasn't yet been officially released and so isn't in the Ubuntu repositories, while E16 I don't like.
So I'm currently installing E17 using a deb package from Cafelinux.org to download and compile it from scratch. It's certainly taking its time, but I'm hoping the results will be interesting.