How Competitive Are Your Keywords?
You can not gauge competitiveness of a term based upon the total number of search results for that term. The best way to tell is to evaluate search results. Pages which have had professional optimization done (page copy & linking campaign) are easy to spot after you know your industry well enough.
Three quick ways to tell how fierce the competition is for any word are by checking the associated ads (price, quantity, and search quantity), using advanced operators, and by viewing the linkage data for the top ranking websites.
Checking Ads
Using Advanced Search Operators
A simple mention on a page is not enough data for a page to be competing.
Page Title
A mention of a phrase in the title is a good indication that the page may be competion.
Google Search: allintitle:"seo book"
Inbound Link Text
The words being in the anchor text in the inbound links is an even better indication of competion.
Google Search: allinanchor:"seo book"
Inbound Link Check
Recently I noticed a simple tool at IBL Check.com, which oddly enough checks the number of inbound links to the top few websites. Once you click the link to check who is linking to each site it pops open a little window showing the URL of each of the links.
McDar Keyword + Link Tool
Another link tool which can tell competition by keyword exists at http://www.mcdar.net/KeywordTool/keywordtool.asp. The McDar keyword + link tool checks the the top 10 Google search results for the number of pages in each site, the number of site backlinks, and the position of that site on the allinanchor Google search for the same keyword.
Link Tools to Build a Linking Campaign
A quicker way to build a link campaign is to evaluate link data on a more mathematical or higher level. A couple inexpensive link tools I think are neato are Linktree (free) & Optilink ($149.)