I've run across this a couple of times before, but I never created a permanent link to it for convenience. Scott Hanselman, guru extraordinaire, has quite a comprehensive list of utilities that he recommends. Its so good, and so extensive, that I thought it would be a nice gesture to post a link to it here:
Scott Hanselman's Ultimate Developer and Power Users Tools List
Of course, there is a selfish method to my madness. Now that it's on my own blog, I'll never have to look for the link again.