I only ever wear or carry stuff with very subtle designer logos on, never anything with in your face printing or large logo names, and certainly never corny slogan tee's, personally I find them so gauche.
However, I just couldn't resist this, fashioned after one of my all-time personal heroes (in his early days):
Obey the Chihuahua! 2-sided Tee by dogs_of_war| CafePress.co.uk
and then I found this, which I got more for a joke to carry to friends' houses, the puppy/people cafe etc with all their bits & bobs in it, what a hoot:
Tease aChihuahua Tote Bag by myhipdog| CafePress.co.uk
Can't believe I spent so many much needed $'s on this stuff, but can't wait until the package gets here!