Here's my build for light cav. I'm currently 1h cav, but the wpf could easily be put into polearms for lancing. I really enjoy being quick on the ground as well as on horseback. Doing so means that I have no IF, which I often miss... but the 7 ath/riding is awesome!
Str - 18
Agi - 21
Conv - 8
PS - 6
Shield - 1
Ath - 7
Riding - 7
WM - 2
1h wpf - 123
Fun build that sacrifices wpf and if for excellent ath and riding skill. 123 wpf is enough to not be spammed, with a reasonably speedy weapon.