1, 2, 3, 4, and 5 are my basic attack functions. I've got Endless Arrows on m5 for easy kiting left or right while firing, and 1-5 with the exception of 3 are my general combo.
Shift 1-3 are my preparatory keybinds, or things that I either don't use while deep in combat or use before combat entirely.
Q and E are my twitch, or reactionary keys. Shrug It Off keeps me out of a stun lock, and I can follow it up immediately with Snare to give myself time to create a gap when enemies are on me.
M5 is my basic arrow attack. I only use this if I'm out of mana. Extremely useful for prolonged fights against more than one opponent.
X is not quite as easy to reach as 1-5, but much easier than the Shift keybinds, and Freerunner is a pseudo-preparatory skill.
C and V are spammable, as often in stealth I need to immediately re-stealth after the effect begins to wear, or I'll be in-stealth and need to get the first Leech off in order to assure a victory against a Darkrunner or equivalent enemy. Alternating in a one-on-on between Tab and C allows me to instantly target another stealthed enemy and Leech them.
Finally, I have Teleportation bound to Mouse Wheel (Up) as you shouldn't be zooming in and out during combat, and makes for a very fast escape when a stun ends, same with Dropback on Mouse Wheel (Down), and really the binds for those two make sense in relation to the orientation and direction your character moves with the skills.
Potions and Food are alt+1-4, for relatively easy use mid-combat or after an escape without wasting time clicking them.