Hello,
The only tags that are truly important for SEO are your title tag, description meta tag and keywords meta tag.
Title - I'm pretty sure you know how to set this per page - which you should always do.
Keywords - usually best set in the master page as they will be the same site wide in most cases.
Finally description, this is usually best set as different on each page using a contentplaceholder in the head section, though having the same description is only a problem if you expect more than just your home page to show up in the results. So if you have two pages coming up in the results, there is a chance that the second may not use the same description in those results. Having the same description for different pages won't directly influence your ranking, only how the second entry may look in the results.
Hope this helps.