One of my colleagues had the year before, and had recently got funding for his startup. He offered myself and another developer a job, so we went to tell our boss together who obviously wasn't too pleased. He then spoke to us separately about negotiations, and he offered me £55k/year. The look on his face when I said "Sorry, but they are offering me much more than that" was priceless.
A few years later (after all the team I'd worked with had left) I went back to what was left of the company as a contractor for a few months. I was earning more per week, than I was per month, when I first started.
Two days before I left, he had been threatening, in a roundabout way, to fire me. But when I handed in my resignation letter, he was eager to keep me and asked what it would take to keep me. I named the salary my next job was offering. "You'll make more than I do now!" he said.
When the sys-admin left I asked for a raise since I was doing his job and my own. They made some excuses about his better education (he was a few hours away from his PhD in music) and the fact the company was under FDIC control.
I found a new job at a local oil company but contracting: my new salary was more than double what the bank laid. My bosses exact words when I quit were "Oh, shit" because he knew all along he'd been screwing me and he was never going to get a programmer/DBA/UNIX sys-admin for $27k/yr.
He asked if he could make a counter offer it was with great satisfaction I was able to reply "Vick, I now make more than you do. What's your counter offer?"