Before optimisation of your site’s copy can even begin many, many hours are spent on the process of selecting the best possible key phrases to optimise the site for. Unless you are certain that the keywords / phrases you are optimising your site for are the right ones, there is very little point in employing SEO at all. However if the best possible keywords / phrases are selected the results will astound you.

The ultimate selection of the keywords is more of an art than an exact science. Each search engine marketer has their own preferences when it comes to keyword research tools - the tools discussed in this article are my top five!

My personal favourite - Trellion's Keyword Discovery Tool, captures data from an impressive 180 international search engines. Compared to Wordtracker, which uses meta-search engines, Trellion's data is far more comprehensive, with the database consisting of approximately 32 billion searches from the last 12 months.

Keyword Discovery features include: reporting on the frequency of searchers for specific key phrases, specific industry keywords, KEI analysis, Keyword Density analysis, related key phrase searches, common misspellings and synonyms as well as seasonal search trends.

For keyword research, the more information you have at your disposal – the better. The sheer volume of data produced by Keyword Discovery will no doubt impress you. While some tools return a few hundred results you have thousands being returned by Keyword Discovery. The awesome project logging feature will save you vast amounts of precious time while the seasonal search trend reporting feature will expose you to the keywords which performed best over certain times (such as the summer holiday season).

SearchStatus was developed by Quirk’s own CEO, Craig Raw, for the highly specialised needs of search engine marketers. SearchStatus is a definite must have for all you search fundis out there and is supported by Matt Cutts, lead engineer of Google, Danny Sullivan, the acknowledged father of search engine optimisation and Geoff Mack, product manager of Alexa. SearchStatus is essentially a toolbar extension that allows you to see how any and every website in the world is performing.

For every site, you visit using Firefox or Mozilla, SearchStatus lets you view its Google PageRank, Google Category, Alexa popularity ranking, keyword density analyser, keyword/nofollow highlighting, Alexa incoming links, Alexa related links and backward links from Google, Yahoo! and MSN – for the first time all in one place.

Like Firefox itself, SearchStatus is an open-source product, requiring no licensing fees and promoting user additions and modifications. Download this awesome SEO tool today!

Aaron Wall, of SEO Book fame, recently released an awesome SEO extension for Firefox users. While this is still a relatively new tool to me, I will be using it more and more with each passing day.

“This tool was designed to add more data to Google and Yahoo! to make it easier to evaluate the value and competitive nature of a market. SEO for Firefox pulls in many useful marketing data points to make it easy get a more holistic view of the competitive landscape of a market right from the search results. In addition to pulling in useful marketing data this tool also provides links to the data sources so you can dig deeper into the data." – Aaron Wall creator of SEO for Firefox.

When activated, this extension immediately provides you with a host of vital SEO information about the sites visible in your Google and Yahoo! Search results. This information includes PageRank, age, links, .edu links, .gov links, del.icio.us numbers, Technorati rank, and Alexa rank. If you’re a Firefox user check out the site and download it today, playing around with this cool tool is fun, fun, fun!

SEO for Firefox also links to some seriously nifty keyword research tools including SEO Book’s Keyword Research Tool, Overture View Bid, Google’s Traffic Estimator, Google’s Keyword Sandbox and Google trends.

Remember that excessive use of this extension may get you banned from data sources (including Google and Yahoo!), it also uses a lot of bandwidth - so remember to turn it off when you don’t need it!

Digital Point's Keyword Suggestion Tool is FREE and displays results from both Wordtracker and Overture to help you determine which keywords and phrases are searched for most often.

The tools coolest feature is that it allows you to enter a keyword/phrase as well as the market you wish to search that term in (i.e. USA/Japan), but the market-related search data is unfortunately only relevant for Overtures results.

Wordtracker is definitely one of the old favourites when it comes to keyword research. With its statistics coming from meta-search engines only, Wordtracker compiles a massive database of keywords and phrases which online users search for. Apart from showing you how often specific keywords/phrases are searched for as well as the number of sites for which they compete. Wordtracker’s related keyword facility will expose you to related key phrases you’d never even considered. An awesome feature is its ability to differentiate between search terms that include capitalization, word ordering and plurality.

An extremely user friendly tool, Wordtracker displays results beautifully - the number of searchers conducted per keyword per day, the keywords which compete with it and the KEI are all displayed in one easy to use table. You can even save multiple projects where your various keyword lists are saved, an export option even allows you to email the list to your client – goodbye cutting and pasting.

Try out the free trial, but remember that this is just a small taste of what Wordtracker can do for you. Subscribe to this tool and you’ll have access to a host of additional features including simple search, comprehensive search, misspellings search, keyword projects and top 1000 reports. The folks at Wordtracker are so confident about their product that they even offer an unconditional money-back guarantee if you're not fully satisfied with the paid service.

These are but five of a vast array of keyword research tools at your disposal. Play around to discover which tools best suit you and keep your eyes open and your RSS refreshed to find out about new tools as well as updates to old favourites.