I would get any 700x23c's your LBS has... I have 23's on my road bike and I do this unpaved 4 mile climb near my house with no problems. I would avoid gravel on city streets because there might be glass mixed in there.
DON'T get too much crap on ebay, it's usually not cheaper with shipping for something like that. And if you always get things on ebay, there won't be someone cool to help you out when you have problems.