Title is the question. You can refer to skills pre-a-certain-change too (just add a "(when it was good)" or "(when it did this...)" to it.
I only really got into templars so will share my idea of the class's iconic skills.
sweeps
blazing shield (when it was more widely viable)
shards (when it had the stun) (even then this kinda a ? in terms of being iconic)
eclipse
(the general vibe of the dawn's wrath skill line, and dark flare with the old empower)
Blinding flashes
BoL (pre the 20+ nerfs, or pre the 360 nerf)
repentance (?) (I WISH the other morph and base of this skill were too)
ritual
rune
These are the skills that let you and others know that you're playing a templar.
They don't have to be the best skills, but I'm interested to hear what skills make certain classes iconic for you!