The number of pages returned is irrelevant. The only thing that really counts are the web pages returned for the listing on page 1. Use SEO quake for Firefox to check the PR, etc.
If the first ten listings are all PR 4 and above then I think really hard about whether it will be worth the effort. But, even if everything is high PR pages, that doesn't mean that you cannot easily get to page 1.
Check to see if the titles and urls are targeted to your keyword phrase. If they are all targeted, then start checking the number of backlinks using Yahoo explorer. Then, decide whether or not the competition is more than you want to tackle.
If there are a bunch of zero PR pages and non-targeted titles and urls, then by all means go for it. With enough backlinks and good seo you can get to page 1.
The key is to never assume that you cannot rank for a phrase.