i only read the original question so far, but i want to say mine was the jason bourne series. one was great, when i heard they made a 2 i couldn' t wait to see it; but i was highly disappointed. haven't seen 3 yet.
Aww man. You're missing out then. I think the third movie was better than the first two put together. Actually, IMO, Bourne Ultimatum has been the best movie I've seen all year; with Transformers a close second.