Before asking about fonts, be sure to check out this website. It is a fabulous resource!
We have no real rules here, but we do offer a friendly suggestion: We love hearing about all of your tattoo ideas, but you might not get the best reception if you say something like "I would love a(n) [insert book/author/etc. here] tattoo! Give me ideas!" Instead, you should probably come up with your own basic idea and go from there. Please do not hesitate to bounce ideas off us, we are more than willing to help, but please do not expect us to be an idea generating machine.