What I actually use while riding: time of day (clock). Temperature, though that's just out of interest so I can talk about how I rode in this morning at -15*F. I don't really need it. The speed, I don't really care, though sometimes it's fun to see if I can break the speed limit through town (30 MPH).

What I use in general: odometer, to know how many miles are on that chain, and it's kind of fun to post a picture of it to my livejournal every time it rolls over another 1000 miles.

That's about it.

I bought a comp with cadence once, but immediately found out that without changing what I did at all, I just naturally spun at about 95 RPM so I figured why bother, and eventually switched back to the Planet Bike Protege 9 that I had before. It does speed, average speed, max speed, speed trend, trip distance, temperature, time, and has two odometers (bike 1/2)

I would not consider a wireless computer. I just don't see the point. Not any easier to install, they just burn more batteries and fail more often and cost more.