1. Geeky T-shirts - This is the easiest way to let everyone know that you are a geek. There are lot designs available on the market. But my all time favorite is the one pictured here (localhost - there is no place like 127.0.0.1).

2. Watches for geeks - You can either go for an ordinary watch with a geeky look or if you are a hardcore geek, you can go for a watch which is difficult even for you to read! For example, Think Geek has a binary watch and you need to practise before you can easily read time!

3. Geeks love sensors - Geeks generally likes anything which measures something. So it is no wonder most of them will go for a device which has the maximum number of sensors. My favorite is the Casio pathfinder series. For example, PAW1300T features atomic time keeping, temparature, altimeter and barometers and yes, it does show time as well!
Another favorite of mine is the wireless weather station. This has the maximum number of readings sure to please any geek!

Where are can I get Geeky stuff?

Following are some of the sites where you can find cool geek stuff!

Think Geek
Fractalspin
ZeStuff
KlearWear