I'm just starting out at SEO work, but I'd agree, too. I've found the best terms to tackle are ones where I can get top listings for minimal work. For the term "search engine optimization" the #20 site in Google has a PR7 with 180 backward links showing in Google (132 links showing in Alltheweb). Yet there are only 1479 searches per day estimated in Wordtracker for this term. I don't think those are good odds, considering that most, if not all, of the sites in the top 20 for that term have a professional SEO firm working on them.
It would take a lot of time and effort, if I could even do it at all, for somebody like me who is just starting out in SEO to get a web site ranked in the top 20 positions on Google for this highly competitive term. I don't think the effort would be would be worth the potential traffic. Plus, this term might get a lot of visitors just looking for tips to optimize their own sites and not just those wanting to hire somebody to do it for them.