I am learning and using Emacs. What I found annoying is that Ctrl-Space input will be stolen by Windows XP to switch the language bar instead of setting the mark in Emacs.
Go to the Regional and Language Options Control Panel. Click the Languages tab, then the Details... button. Click the Key Settings... button. Double-click each entry in the "Hot keys for input languages" list and make sure the checkboxes are not checked. (If they are, uncheck them and click Ok.)
You do not need to disable the language bar, just the hot keys.