I'm not sure how it works in other version of D&D, but in 4e you get absolutely no bonus to defense with your weapon, and that doesn't quite make sense. When you're in combat with someone, you ...
Can wizard's staff of defense class feature stack with Wizard Utility 2 Shield on the same triggering effect?
Staff of Defense class feature: ...once per encounter as an immediate interrupt, you gain a bonus to defense against one attack equal to your Constitution modifier. You can declare the ...