Nailing the Coffin Shut on the "Don't Link to External Sites" Philosophy

Rare is the month that goes by when the spectre of the none-too-solid argument for hoarding link PageRank and link juice doesn't rear its ugly head. And since I've just spent the last 5 hours on Q+A duty (as our beloved Q+A manager, Jane, is on vacation), and in need of a short punchy post, I'll make this brief.

Arguments against linking out to other sites:

1. If the original PageRank formula holds true, and no other algorithmic elements are in place to benefit sites and pages that link out, you could be costing yourself a small fraction of potential link juice.
2. Visitors might click those links and never come back to your site.

Arguments for linking out to other sites:

1. You tend to get more links coming back in (evidence)
2. Your domain and pages appear in the referral analytics of other sites, inviting site owners (who are often very likely "linkerati") to check out your site
3. The search engines have at least looked into algorithms that reward external linking behavior (like HITS)
4. Karma - and not just the invisible, metaphysical kind - bloggers really do look at who links out and who doesn't and they tend to reward the more generous
5. In any type of "neighborhood" link analysis model, a site's outlinks can be used as a good predictor of a domain's relative trustworthiness
6. Readers and web visitors can derive value from the links you point to, and they can help to prop up the credibility & association of your own site. Note this research about memory association & repetition (and apply it to the marketing world rather than the political)
7. Sites that don't link out are extreme outliers on the web's link graph and thus, may fall more easily into negative classification schemes (particularly if they're run by overzealous, over-optimizing SEOs) :-)
8. Never linking out doesn't keep visitors on your site any longer, it simply means they'll jump away via the back button, bookmarks, a browser close, or a typed-in address
9. Pete has a few more good reasons on his post - Quit Hogging All The Links!

What do you think? Is there anyone who still practices the never (or rarely) link out philosophy?