I tend to favor left control, and right shift myself... discovered this using a KB where the up arrow was at the edge of the right shift, most annoying keyboard to type on ever... all of the sudden my typing is in the middle of already typed text. If typing while looking at something else, I'd see a garbled mess too often.
Do you have very large hands or a narrow keyboard? On a normal 85-key "75% keyboard", I cannot reach the up-arrow key with my pinky while the rest of my fingers are on the home keys.
I've had similar cursor problems with those keyboards that have page-up and page-dn next to the up-arrow key. Just a little finger displacement when trying to left-arrow and the cursor is suddenly inserting my subsequent typed text far from the intended location.
