Me, I'm a little weird. I don't like activating abilities using the keyboard. Luckily I use a gaming mouse, so I was able to map my most-used abilities to my two extra mouse buttons and mouse wheel click. I mapped the mouse wheel's scroll up/down to switch the current ability page, so now I have 4 pages with 3 abilities each that can be used with the mouse alone! :D
Less-important stuff I just click; so far these are just buffs and highly situational abilities anyway so it's no great loss.
I use Q,2,E,R,F, and C for my abilities. I use shift + one of those 6 buttons for more skills placed in the bottom center skillbar. I use shift + mouse wheel to go to my second set of skills.
I is my skills tab O is my guild tab P is my friends tab L is my mission log N is my character sheet K is my crew skills J is my abilities tab
- on the keypad is my ammunition reload button + is mapped out to whichever health consumable I have placed on my right hotbar Ins is my hp+ammo regen ability out of combat. Shift + Space is target next enemy TAB shows me all the people in my instance/planet ~ is my options tab 1, 3 and 4 select different types of cells I use (Plasma, Ion and Elemental)
I think that about covers it. Most everything else I completely unmapped or left alone, but I did change roughly 90% of my overall default controls.