Below are some useful resources for every website...
1. Google Webmaster Tools - a suite of website tools for diagnostics.
2. Sitemaps Pal - generate XML sitemaps for Google, Yahoo and Live search engine spiders.
3. Google Analytics - free web-based tracking software.
4. Template Monster - commercial website templates.
5. Paypal - online payment service for receiving payments via credit card.
6. Wordpress - free and most widely used blogging software.
7. Webmaster Resources - human-edited directory of webmaster resources and free web tools.