As a nail tech, I can tell you that getting a pedicure is the BEST thing to go for!!!! Your feet take a beating every day and need the most care... it's also the most relaxing of the spa services--aside from a full massage. For the best experience, avoid those discount nail salons--too much traffic for relaxing.
Silk Wraps are for reinforcing your natural nail, they don't serve well as artificial nails alone. If you have fairly strong natural nails and just need a little extra help in keeping them from breaking this would be a good option for you.
Go for a specialty pedicure! Don't skimp on the price, you want the best!
Things to avoid... foot razors! Only a medical dr should be using blades (most states they are illegal but some get away with it because folks don't know they are) Avoid any tech that's not willing to explain proceedures, and run like the dickens if the footbath isn't clean or they pull their clippers (metal instruments) out of a drawer (they should be in a sanitizer bath or sealed packages) and make sure they use NEW files and such (the disposable stuff).
Massages are great if you like them (I've always been too weird about people touching my body to be comfortable) and no, you don't have to be totally nude. Explain that you are nervous and they will understand... ANY respectable massage therapist will be more than glad to accomidate you to make you comfortable!