I have a progressive solution for warm biking hands.
+3C and up - regular bike gloves
+2C to -15C -
MEC Nanu lobster mitt/gloves [so much better than PI lobsters, it's not even funny]
-15C and colder - the MEC Nanu in combination with home-made pogies.
I have very cold hands [confirmed by my wife on numerous occasions], so it's almost impossbile for me to get sweaty hands from riding in too-warm gloves. We sometimes get Chinooks in the winter, which means I ride to work when it's -10C and ride home when it's +10C. If I know it's coming, I'll take my regular bike gloves with me in my pack.