Most of us don't shift items that much during battle. You try to get the best items for a general situation and minimize swapping. Besides you still have to watch your weight for encumberance.
What I carry with are the potions, wands, and scrolls for extra spell power. I have them for the major fights.
Edit - there used to be an item database at the top of the forum, but the link needs to be fixed since the account is gone.