I have this problem too, even though i had my car aligned by a "hunter" laser alignment machine by a professional race shop (Group 2 Inc. for Seattle-ites) for all four wheels... but i still have this exact same problem, where the car pulls to the left, and i have to keep the wheel cocked slightly to the right
it IS annoying. annoying as hell!
I was hit in the rear at 5 mph once... do you think it might be frame issues?
PS: I've also carefully noted tire wear through the last 10,000 miles, and it seems to be even. I check my tire pressure every week too.