I've never seen the point to WASD. The keys on a modern keyboard aren't laid out with gaming in mind, and really aren't laid out with typing in mind either! Older computer books advocated keys laid out in a diamond pattern for cursor control (as opposed to the linear arrangement on, say, the Apple ][ ) but nowadays everyone is used to the inverted "T".
The arrow keys make sense for directional movement, and there's plenty of nearby keys for functions. WASD puts too many like keys near eachother; it becomes to easy to hit the wrong key. I usually map the arrow keys to classic "doom-style" arrangement with forward and backward handling linear movement and left and right turning. Then I map the strafe modifier onto the second mouse button so it basically converts the mouse from looking into moving, so it handles forward and back while held as well as side to side. This is also useful for precision movements.
As for actions, I put primary fire on mouse one (duh), jump to "Shift" (right under my left pinky), crouch to right control, and action to carriage return, or, in the case of a secondary fire, it gets carriage return and action goes to the space bar. (A holdover from "Doom") I usually put the run/walk modifier onto the "?/" key since I don't use it often (either crouch or use strafe modifier to move slowly as I set "Always run" to on).
Some games don't include a strafe modifier so then I set the arrow keys to strafe and mouse 2 to secondary fire. I think Medal of Honor uses this evil system; it makes it hard to switch to another game and back again -I try to strafe as I normally do, and, look! A grenade at my feet! Oops! *Boom*