I really like syncing things up in subtler ways than throwing effects or flashes everywhere. Like having someone raise their hand on beat, or shift movements on beat, using the action already in the shot to convey the motion of the song. I've always called this 'motion sync' or 'coincidental sync'.
As for other types of sync, I like them too. Lyric sync is actually a lot more difficult to pull off than most people realize. The problem with lyric sync is that the viewer is trying to focus on the video AND the song at once, so if you have a cool line like...hrm, "tell me why....I need another Pet Rock," and then you just flash a Pet Rock on the screen, or have a scene with a rock in it, it may not click in the viewers mind. But if you start panning a Pet Rock across the screen before it mentioned in the song, the viewer is gonna wonder "why is THAT there?" and then they will switch focus to the lyrics just in time to hear 'another Pet Rock' and hopefully enjoy the lyric sync.
Also, from a video I'm working on now, there is a line that goes "and it's you, the star that guides me when I'm lost at night" and I have a scene of a girl coming down from the ceiling on a wire harness to make her look like she's flying. To me that's a pretty obvious lyric sync, but it might not be so obvious to someone else. Lyric sync is very viewer-intensive AND very viewer-dependent.
Effect sync is easy, but it has to be effective. Effective effects to me are effects that not only look interesting but don't heavily distract you from what is going on in the song and/or video. Euphoria's effects package is brilliant; it's enough to captivate, but if you take the time to look in all the circles and Kooptangles, you see a well done, well synced in other ways video as well. You can't just have bars and waves everywhere bouncing on beats and expect that to be enough.
Strobing beats is old school. I appreciate the classic techniques.
Mood sync is awesome and again, very viewer-dependent. Going with mood sync is color sync which is something I've read a lot about but have only experimented with a few times. Certain sounds give certain colors. So do certain moods. Slightly blueshifting your video gives it a cooler, sadder feeling, redshifting makes it more aggressive and warmer. Again, somewhat viewer-dependent.
Eep, long post is long...
