Heres a list of a few i use
Xenu Link Xenu is a great little program that checks your sites links and compiles reports of any badlinkage internally and externally on your pages (whole domains at a time) Also can put a report on your server listing dead files/pages/images and create detailed and nicely laid out site maps.
Overture Keyword Selection Tool. This one is great one for getting a general idea of what people are searching for.
Seo Chat The tools are found on the left .... Link Popularity, Meta Tag Generator, Domain Typos, Keyword Typos, Keyword Density, Keyword Optimizer, Google Keywords, Overture Keywords , PageRank Search , PageRank Lookup, Future PageRank, Site Link Analyzer , Meta Analyzer , Google Dance
DNS Stuff For whois and reverse lookups etc. Handy shit here.
Magpie RSS is an open source RSS parser written in php. Nice and easy to use and quite adaptable.
Obviously i need to add
Word Press and also these to match with it.
Wordpress Plugins and here is a nice batch or
Wordpress Theme Browser
Next thing that i dont care to list all of is MESSAGE BOARDS, there is an enormous vault of knowledge across the adult boards and if your smart enough to be able to sort through the DRIBBLE you can find some true GOLD on them.