I too carry a Classic on my keyring, now in two variations, since those kindly folks at Victorinox make different variations. I carry at the moment in urban situations one that sports a very useful ball point pen. I believe there is also a Classic that sports a small LED light.

In the field, I carry the classic Classic with the ever popular tweezers and toothpick. I really like their tweezers - great for the occasional cactus spine.