37signals is the great bunch of folks behind some amazing stuff: Basecamp, Backpack, Writeboard, and even Ruby on Rails. I haven’t used Ruby/ROR, but I’ve been really, really impressed with Basecamp and Writeboard. These folks are golden.
They’ve just released a PDF-only book titled “Getting Real” about the process and mindset they use to push out all this amazing stuff. I haven’t bought it yet, but I’m definitely putting it on my booklist.