For as many times as I saw the Lord of the Rings movies in the theater, and never once thought I was wasting my money, suffice to say they were FILLED with moments like that, for me. A couple more specific, equally geeky, but more abstract to the point of meta moments:
The beginning of Hitchhiker's Guide to the Galaxy (well, after the song ended anyway). Looking forward to new material from Douglas, knowing how many YEARS he put into making that happen. The movie itself was so-so, but just that there WAS a movie brought a tear to my eye, and wished Mr. Adams had lived long enough to see it. I imagine I'll feel the same way if Ender's Game ever gets made (and hopefully Card will get to see that one).
The opening title scrawl of The Phantom Menace. One of my earliest memories is of watching A New Hope on Super 8 at my Uncle's house, as well as the christmas special (both memories I doubted until confirmed MANY years later). I was 6 when the last new Star Wars film came out and remembered seeing it in the theater, and then again at the drive-in (double feature with the Dark Crystal). I can't remember life without Star Wars; I'm not the most obsessive fan, but I've always enjoyed the films (even the TV Ewok movies!) For that moment, opening night, I was once again 6 years old, watching the receeding text and anticipating what was to come. It's a shame the movie wasn't that good, but that moment? Pure magic!