One of my favorite openings to a show. House has an opening with very surreal music and nice artistic effects that gives off an almost dream like quality.
Another one of my favorite openings to a show is Samurai Jack. Such an awesome show with an awesome opening.
Star Trek Enterprise may not have been one of my fazvorite Star Trek programs, but it had one of my favorite Star Trek openings.
And of course there is JAG. Used to watch this show all the time with my dad and I always found the opening catchy.