Okay, you started it, Shroom! I could go on ad infinitum, but I'll spare you all. :rolleyes:
This is a favorite series of mine, both the books and the movies. I own all of the DVDs out so far and watch them periodically. I own all seven books and revisit them, too (as I do with the Lord of the Rings trilogy).
I felt the first book was great; the second, less so; the third stronger, and things kept improving right up to the final page of the final book. I won't reveal spoilers (I consider that unprincipled!), but if you haven't read all of the books, you're in for a real treat.
The teens who play the main characters (and I include here Neville Longbottom, Draco Malfoy and Ginny Weasley) have indeed grown in to their roles. To be honest, I thought Daniel Radcliffe's acting in the first two movies was wooden. He has developed into a good actor, IMHO. I much preferred Richard Harris as Dumbledore to Michael Gambon's portrayal.
I loved Order of the Phoenix and look forward eagerly to seeing the final two films- although it'll mean the end of the road for the characters and that wizarding world in all probability.