vim highlights matching brackets which is nice until it starts becoming a pain. This in your .vimrc will turn it off:
let g:loaded_matchparen= 1
From here : http://groups.google.com/group/comp.editors/browse_thread/thread/42daad5f97aa6f13/9e140069098c7560?lnk=raot
You can still bounce between the matching brackets by pressing %.