What SEO Tools do you regularly use?
Most good SEO regimes, in addition to developing on-site and off-site aspects, will measure successes through something along the lines of a browser toolbar that shows PageRank and Alexa rankings, among other things.
Other good tools for your disposal are backlink checkers (about a million of these exist, so pick a couple and compare their numbers; go with the lower one as the accurate count), site graders (again, there are a couple of these, mostly freely available), and something along the lines of an analytic tool that checks for incoming link anchor text (so you can optimize it as much as possible; this may be hard to find).
Finally, a great on-site analytics tool to see your search engine/organic traffic is very important! You’ll want to check the terms people are using to get to your site, and what kind of activities they do once they get there. I wholeheartedly recommend Google Analytics for this.