I always fly 1B or 8B (if available) -- bulkheads.
I always have a backpack when I fly solo but a large Briggs & Riley carry-on if I fly with a girlfriend or family.
I've seen full overheads a handful times, including the newer larger overheads, but probably less than 10% of flights where it was a hassle to shift stuff around.
I much prefer to board last and roll into my seat when I fly alone, tho.