I've been using Linode for about 4 years now for dev and [small] production servers. They're such a joy to use. I agree that I could probably get VPSs cheaper somewhere else, but ... meh. And, though I rarely need support, Linode's support is second to none and it's a real help with something's going wrong. More than anything, I'm happy to pay a bit extra to support quality products and services.
So, joining the chorus: happy birthday!