Certainly a T-shirt, but also a record-bag kind of thing would be nice, as long as it's good quality (and there's the problem as this will cost more). Perhaps something to buy and have delivered later on.

I must admit I don't have much use for stickers or baseball caps (cricket hat perhaps ) and really branding USB sticks is a bit of a waste of money considering that they sit in your pocket for most of their lives and are so cheap that no-one really needs a freebie.