A few little things (not really plot holes but anyway): Why does Vader stop Boba Fett from shooting Chewbacca in ESB? Doesn't make much sense to me, surely a man like him would place no value on the life of a Wookie.
In ROTJ, we see the Rebels placing explosives in the shield generator. Then they run about five metres away and hide behind some bushes. There is no way they could have escaped uninjured from the truly massive explosion that results, IMHO...
Why does the Death Star bother to orbit the planet that is in the way of Yavin? (Or is the planet called Yavin, can't recall) Why not just blow both planets away? Would have been much quicker... Also that display the Rebels had showing the Death Star approaching: What exactly is the use for this display when there are no Death Stars around? :-)
Luke could use the Force a bit more in ROTJ, for example to push/pull the stormtroopers off their speeder bikes...
That's all I can think of for now. Not important things but just wanted to see what others think...