Applications for Mac:
Alfred: A application for Mac that lets you launch applications, open files and folders, do simple math and define words (and more!) all at the click of a button. Perfect for those who are getting mouse fatigue.
Time Tracker: My preferred time tracking app. It's easy to split up into clients and tasks (no client tab yet, I use the Projects tab to separate clients, since I don't need to separate my actual tasks)
Cyberduck: A decent, free ftp client.
Skype: Not new to a lot of you, but the desktop sharing feature is invaluable when you want to have a meeting discussing initial designs (or even second, third, fourth drafts) without actually leaving your house.
Free stuff:
Dreamstime: A stock image site that has decent free images, perfect for the client who wants everything but wants to pay nothing.
Veer's Free Stuff page: Veer (an excellent stock site) gives out weekly free photos and illustrations. Free fonts monthly.
iStock's weekly free stuff: Every week, iStock gives out one free photo and illustration. iStock is better than Dreamstime, but not as good as Veer for quality images, in my opinion.
Font Squirrel: Great free fonts with a commercial license.
40+ Excellent Freefonts for Professional Use: An article from Smashing Magazine that I keep going back to again and again.
Online resources:
The Photoshop Etiquette Manifesto for Web Designers: A great site to help you create photoshop files that won't leave your web developer cursing your name.