ESDF opposed to WASD is one of the few 'major' yet simple changes you can make as it frees up Q, W, A, Z, and X on the left side.
Movement: E S D F
Self Heal: A
Weapon switch: all shifted one to the right (1 nothing, 2 melee, 3 sidearm, etc)
Money: Mousewheel scroll (throwing around a thousand pounds in 1 second at the last wave is always fun)
Previous Weapon: Q
Flashlight/M14 laser: Mousewheel click
'Use': Z
'Stat all': I
'Stat none': O
Adminlogin <pass>: N
Enter/return: Talk
Not sure if I have any other controls changed.. but those are the important ones. Mostly personal preference, but some might be easier.