I'm not gonna tell you what you should or shouldn't watch. That's a decision you have to make for yourself. I do think its important that you know why
you feel you shouldn't watch something. Is it because you feel guilty watching it, or is it because someone told
you that you should feel guilty? There are lots of Christians out there who pretty much stay away from any form of media that isn't overtly Christian, and that's fine for them, but I don't think you're gonna find many people here who have that outlook.
I believe that whatever you decide to watch/read/listen to is your decision, and only you know what kind of effects its having on you. I think its always important to remember that entertainment is just entertainment. In my opinion, it shouldn't be taken too seriously; unless of coarse you're worried about what your young kids are watching, but that's a whole other issue.
There are, however, allot of Christians who don't feel comfortable watching stuff with lots of "magic". If you don't think its good for you to watch that, maybe you should find something else. There are plenty of good anime out there that aren't as heavy on it as I'm assuming Sailor Moon is (haven't watched it myself yet).
Whether you decide to watch more anime or not, feel free to post here and hang out.