Things that are useful! If you can put your company name and contact info on anything from a crank powered flashlight or a bottle cap opener, then you'll get peoples attention. But you'll have to match the promotional item with the right target clientèle and you'll be golden.

It's more important WHAT you put on something than what the something is.

Make sure you have a really noticeable, even startling brand. Something funny and unusual.

For example, instead of "Smiths PC Repair" or "Dependable PC Repair" try something like "Son-In-Law PC Repair: You couldn't get better service if you daughter married him!" Good conversation starter, and people will remember it.

That said, I like T-Shirts. You have room on them to make something funny or memorable, and they aren't too expensive. And if they are well designed, cool sayings, something people are willing to wear, they not only remember you themselves, but become walking billboards. Just remember to make it something worth wearing - no plain-logo-over-the-heart shirts...