There is nothing wrong with keeping in touch with ex's. Just because you decide to no longer be involved romantically with someone it doesn't mean you can't hang out, talk, go to lunch or dinner, or even vacation with each other. I find it therapeutic most of the time to tell you the truth. You can see if things that bothered them about you are still issues in your life and vice versa.
Hell...every single one of my ex's by any man's definition is fucking hot and I like their company and the attention when I take them out. I like the way they look, the way they smell, the way the dress, the way they walk, and fo sho the way they fuck. No I do not fuck all my ex's. Yes, with enough time gone by I would fuck all my ex's again and again and again. Don't get caught up in sentiment and things will work out just fine.
Oh and if you truly don't want her bugging you anymore there is one proven method to do so....DON"T FUCKING REPLY. To her calls, emails, texts, IM's, myspace messages or fucking smoke signals. You reply and that gives them fuel. It gives them hope. This is the only way to take someone out of your world permanently.