A quick short post on some research sites for good keywords.

With volumes -
Wordtracker: freekeywords.wordtracker.com
Keyword Discovery: keyworddiscovery.com/search.html
Wordze: wordze.com

Without volumes -
Adwords Keyword Tool: adwords.google.com/select/KeywordToolExternal
Google Sets: labs.google.com/sets
Keyword Group Detection: adlab.msn.com/contextSim/Default.aspx

Related -
Adwords list generator: tools.seobook.com/keyword-list/generator.php
A shitload of other keyword tools: tools.seobook.com/keyword-tools/

I am currently busy so updates may be less frequent.