Sticking firmly in on page seo territory, I regularly link out to other quality relevant pages on other websites where possible and where a human would find it valuable.
I don’t like to link out to other sites from homepage. I want all the PR residing in the home page to be shared only with my internal pages as much as possible. I don’t like out to other sites from my category pages either, for the same reason.
I link to other relevant sites (a deep link where possible) from individual pages and I do it often, usually. I don’t worry about link equity or PR leak because I control it on a page to page level.
This works for me, it allows me to share the link equity I have with other sites while ensuring it is not at the expense of pages on my own domain. It may even help get me into a ‘neighbourhood’ of relevant sites, especially when some of those start linking back to my site.
Linking out to other sites, especially using a blog, also helps tell others that might be interested in your content that your page is ‘here’. Try it.
Generally I wont link out to sites using the exact keyword /phrase I am targeting, but I will be considerate, and usually try and link out to a site using keywords these bloggers / site owners would appreciate.
I try to be considerate when I have the time as anchor text in external links is ultra important and really does have an impact on rankings for others – and me.