Warning: This list is entirely subjective, and only includes artists whose releases I personally enjoy. I skipped linking a few dozen of my collection's most marginal acts, as well as classical names. This is primarily a personal reference tool, but others are welcome to borrow its usefulness.
I have selected the best links I can find, after careful research. Off and on, it took over five years to fill in a link for every name (page first "finished": March, 2003.) Further links get added as new favorites arise. The page is also regularly monitored with link-validation software -- the success rate of these links is much higher than on any other such site I've seen. Still, there are always a few broken ones. Email me to point out a dead link, or a link which might be upgraded to a better location.
Last added links: Deerhoof, Matt Elliott, the Feeling, Fleet Foxes, Gutter Twins, the Last Shadow Puppets, Mogwai + multiple "Shopping list" names
Recently updated (as of 11/10/09): Belly, Big Black, Frank Black, Dave Brubeck, Chariot, Cream, Julee Cruise, Dinosaur Jr., Bryan Ferry, the Fiery Furnaces, Wild Man Fischer, Fluid Ounces, Kristin Hersh, Scott Johnson, Van Morrison, Neu!, Ken Nordine, Pizzicato Five, Poi Dog Pondering, Portishead, Rainy Day, the Vaselines, Paul Westerberg
Need fixing: Afghan Whigs, Finn Brothers, George Harrison, Living Colour, the Moog Cookbook, Napoleon XIV, Yello, John Zorn and a dozen or so Geocities links which have freshly died