Pretear (2003) - Practically Perfect Mahou Shoujo
If you want to get someone started on the mahou shoujo (magical girl) anime sub-genre, start with Prétear.
At 13 episodes it just the right size for starts (something like Cardcaptor Sakura might scare someone off; 72 episodes is quite an investment). At worst one or two eps might be considered filler, but for the most part the story keeps driving forward because there's no time for dilly dallying.
The characters are all sympathetic including the bad guys, maybe especially the bad guys. Being a fairy tale, the ending is not a cop out.