You also have to consider that your page is optimized keeping the sales in mind because if your pages are not sales oriented than no number of hits will benefit you.
I don't think so there can be something called Good value. It varies. For a start up website, even 1000 uniques per day is good. You just see the pattern and make sure that the pattern shows an upward trend.
Hits and Page Views is almost the same definition. it is the number of page of which your site is visited. the visitor only click your site once.
Unique Visitors is the first time and returning visitors of your site which the visitors navigate your site to find useful information.