They do both contain similar plot events, but that's hardly enough to say that they carry the same theme or have similar plot structures. Fight Club is a movie about a man with dissociative identity disorder that starts up underground fist fight clubs to eventually form an organization to overthrow the government. Collateral is about a man put into an unbelievable situation and how he has to overcome his own feelings to get past it.
I like both movies, but I have to say that I enjoyed Collateral much more than Fight Club. Collateral is one of my favorite movies...I was amazed while watching it.
Excellent plot similarities that you noticed though. Like jake said, good screencaps too to prove your point.
-Lasereth