Of course I'd take a pair of trousers. Don't want a zombie taking a bite out of my...*clears throat*...dongle.
And I don't like to exhibit it, and during a zombie brawl, it would just distract too much. I'd get a pair of shorts that I'm wearing right now. When I can choose only one article of clothing, it will alwaysbe pants. They only help, a fedora can easily fall off, or distract you. It's pointless.
Also, you would use your bass guitar to kill zombies? What are you, mad?!
But since I have a guitar AND a bass guitar (which I use far less than my guitar), then I guess that'd be a decent weapon against them. Alternatively, that skateboard that I have hidden away somewhere (though I know the general area where it is and can easily reach it).