Taking a date to a SC. Good idea or not?

I say go for it. You have already let the cat out of the bag by telling her you go occasinally, so she already has that ammo if in a fight. She is expressing an interest, if you do not take her she will fill in her own blanks as to what exactly goes on and you know it is going to be way over exagerated. Take her to a realivity by the book club (ie where she doesnt see girls going over the line) and also one that you do not visit that often, dont want to be walking in and have 5-6 girls calling you by name :)
IF you get her a dance be prepared, a healthy percentage of dancers are bi sexual, so if your girl is hot they will probally have a little fun with her (remembe most places have a touch and go polikcy, you touch you go, however the girl can touch all she wants)
IF it does get a little hot and she comments on it, you always have the Damn they never acted like that with me, it must be cause of you.
As always have fun with it!

SuperDude is right on the money on the fact that you have opened the door to some problems.

Another issue is your girl might like other girls. Bringing her to the SC might rekindle a fire from her high school/college days with other girls. That usually does not help to build your relationship with her.

Thread carefully with this one. The most likely consequences are negative. She might become jealous of the girls, like the girls and forget about you, or be suspicious of you.

A lot depends on the strength of the relationship. If you take her, be prepared for her to feel awkward and threatened. The next time she gets angry or wants to pick a fight, she will throw the visit in your face, accusing you of lusting after or fantasizing about a dancer instead of caring for her. A lot of women are curious about the SC, because they (1) want to compare themselves to dancers;(2) want to invade a male preserve or (3) just want to learn as much as they can about they guy they're with, including all of his hobbies. You have already opened the door by telling her so a refusal to take her will arouse suspicion. Taking her will give her ammunition for her the next argument that starts over her not getting enough of your time or attention. Proceed at your peril.