I'm not doubting you might be having hardware problems, but several of your complaints are not actually problems.
Move windows between Spaces: Hit your spaces key, and drag the windows between spaces. Easy peasy.
Automatically change desktop wallpaper: right-click (or control-click) on desktop, select "Change Desktop Background". I have a folder of Digital Blasphemy pics, so I hit the + button at the bottom of the left hand side, and navigate to that folder. Then I check "Change Picture", select "Every Hour", and check Random Order.
I have a feeling that Spaces is "supposed to" separate things by application, not necessarily by window. Linux and Windows throw all windows into one huge Alt-Tab clusterfsck, where Apple says: Command-Tab is for switching applications, and Command-` is for switching windows within an application.
Menubar at the top of the screen? Ever hear of Fitt's Law?
Rather than the fiddly wasted screen space of dozens of menu bars repeated in every window, I've just got one.
Uninstalling Garage Band? Just delete the folder. No uninstaller application needed.
Just because something is different doesn't mean it's broken