For a bike computer...
current speed
max speed
average speed
trip distance
odometre
trip time
clock
stopwatch**
splits/laps**
cadence*
multiple wheel memory*
wireless**
* = stuff you can really use and should look for in a high-end computer, but you live without if you have only one bike and you're not into too-disciplined training.
** = stuff that'd be nice to have, but you won't miss unless you're a bike tech weenie [like me] and anal-retentive about training [like me].
I don't think such a beast actually exists with all of these features, unless you get one of the Polar S series HRMs [I have the S510], which also give you heart-rate info and computer downloads... but they're pretty pricey.