To Link or Not to Link

There has been much speculation over what is a good link and what is a bad link. Most of the time if the site is relevant to yours you would want to link, unless the site is a PR (page rank) of 2 or less. Even so, 1 or 2 sites that are low PR may not hurt your site, only provide more traffic or make it more noticeable. The more sites that your site is linking to makes more opportunity for your site to be in front of someone that would not normally make it to your site. Free directories (www.dmoz.org is a good place to start) and industry specific databases are a great place to start, especially with a moderate to less than moderate budget available for your website. If you are asking for someone to link to your site keep in mind that any links in and out of their site helps their rankings as well.
When you want a link to your site expect the other party to request a link back to their site for a reciprocal link, so you may want to develop a relevant links page for easy navigation for search engine spiders to find and crawl your relevant links. Burying your relevant links, may upset your link partners or the spiders in general and they may not crawl all of the sites. There is an undisclosed point structure for all items in an SEO strategy which provides enough information for a search query to search engines when anyone is using the search engine.
Everything adds up to equal your search engine rankings from page title, to meta-tags, to links to every last bit of text on your site, so be careful and very inquisitive when being requested to link back, not everyone does everything by the book.