Well Paul, I'm glad you enjoyed the movie, I wanted to address your two questions at the end.
Number one, Vader did not recognize Luke as his son at first, in A New Hope when he's chasing Luke in the Death Star trench he says the force is strong in this one, no indication he has any idea other than that Luke can use the force. And of course having the name Luke Skywalker, which could easily have been found from captured rebels or communiques didn't hide his lineage very well once Vader came into contact with him. OTOH, Leia never used the force to be sensed by Vader, and even after discovering Luke he wouldn't suspect having another child, he had no clue Padme had twins. Also, and I may be wrong on this, isn't it the Emperor who first names him as the son of Anakin Skywalker? I'd have to rewatch Empire for that.
I've read a few things positing your question there, but as far as I can tell from the offical line it's either no, or who knows, but probably not. As far as Lucas has said he's the chosen one broguht about by the force itself.
FInally a note on your P.S, I've also read it questioned wether Vader, through use of the force, drew on Padme's life to sustain his own after being injured. After rewatching the movie I don't think the timing quite fits, but it is an interesting hypothesis none the less.
