Well here is the list of SEO tools that i usually use and trust, alot of people go here and there and are always unsure about which tool to use, so here we go.

SEO Tools

Pagerank tools
http://digpagerank.com/
http://www.seologs.com/pr-check/pagerank.html

Backlink Tools
http://www.seologs.com/link-popularity-tool.html
http://www.seologs.com/link-analysis-tool/backlinks.html
http://www.seochat.com/seo-tools/link-popularity/

Indexed Page Checker
http://www.seochat.com/seo-tools/indexed-pages/

SERP Rank Checkers

http://www.ventio.se/seo-tools/google-position/
http://www.seomoz.org/rank-checker
http://www.shoemoney.com/serps.php
http://www.seochat.com/seo-tools/search-engine-keyword-position/

Extra Tools
http://www.seomoz.org/page-strength/