When I woke up this morning, all the lights on my DGL-4100 were out. I checked the output of the power adapter with a voltmeter, and it was 0V.
I took a power adapter from another D-Link router, and connected it to the DGL-4100, and it's working fine now.
I've bought two D-Link routers in my life, and with both of them, the power adapter has failed. However, with the first one (DI-604 I believe), support was very nice, and sent me a whole new router. This time, they wouldn't even talk to me unless I paid them.
I've never had an issue with any other brand, and the first issue I had with D-Link wasn't enough for me to stop buying D-Link, because of how helpful support was. But if you're going to sell me a faulty product and refuse to support it, you've lost a customer.