Definitely agree with banddirector514 here, check out some SCV cymbal stuff. One of their most famous visuals, known simply as "the Viper," can be found at the end of this video
here.
It should also be noted that before you go putting visuals into the show, you need to make sure that you have the best quality of sound you can achieve. A lot of times, with high school lines, the cymbal line forgets about this, but this is the cornerstone of any good cymbal line. Are you getting a full-bodied crash/choke/sizzle/ting sound? Are you playing with good technique, like an "A-V-A?" Is everyone on the cymbal line playing at a uniform height?
Also, you can't just have someone pick up a set of cymbals and expect them to play comfortably. It would do a lot of good to have a daily warm-up, stretch, or workout of some sort with the line. You could do what are called "clock drills," where you have one person in front of the room calling out different clock positions, and you hold your cymbals out (facing front, facing outward) at the called-out clock position. For instance, "3:45" would have your arms completely straight out. Sounds trivial, but the muscle memory you develop from stuff like this really improves control over the cymbals, throughout the entire body, especially the core.
It's very important that you address some of these things first, and make sure that you have them down pat before you start complicating things. Just the same with the upper battery, you can't have a lazy sticks-out or -in, you can't have a lazy cymbals-up or -down. Cymbals are a really understated instrument. They are not easy to play (at least with proper technique, control, and good quality of sound) and can be really fun to watch. Do yourself a favor and have your line watch some DCI/WGI cymbal lines, even some I&E performances, just for some inspiration.
Here's a few of my favorites:
SCV 2001 Cymbal Ensemble (In this one, they play the intro to Tool's song "Eulogy." Cool as anything.)
SCV 2006 Cymbal Ensemble Magic of Orlando Cymbal 2005 Line Music City Mystique 2006 Cymbal Line Sorry for the lengthy response. Just remember that cymbals are what you make them, and a good cymbal line is really something cool to watch.