Nice proxy site you've got there. Is that a custom design? Anyway, price would depend on the revenue you get for it.
It is good because it doesn't contain the word "proxy", but the dash is not good for SEO (according to some people, I don't have experience with or without it). However, it is good and rememberable, which is good for getting some traffic from word to mouth. If you are making good revenue from it (I mean adsense revenue, not Widgetbuck. I think they are more like scammers and no one will be paid), I suggest you don't sell it, focus on promotion instead.
AdSense is your personal account and you can not sell it. You can just provide a screenshot for proof of earnings (hiding the CTR, CPM etc, show only the earnings and impressions to avoid banned account). You just sell the site.