Ideally, you have to use description tags which are related to your web page... In case you are using same description, you will get duplicate description tag error in Google Webmaster tools. Moreover, Google will pick up a relevant snippet from the web page and display it as description for your page.
Your description should be difference each page. That description also importance to increase CTR on search engine result page
Don't use one title for the whole website, use different title and meta description for the different pages.