I have aero carbon tubulars as race wheels and short/fast group ride wheels.
I don't care that much about power data (until the garmin-look pedals come out in March, then Powertaps will become obsolete)
I would use clinchers for long rides (>20 miles from the car/home/etc.) for the ease of flat changes. You can ride home on a flat tubular for a reasonable distance. Flats on tubulars will cost much more $$$.
Ksyriums are great wheels in general.