I was having some serious cable connection issues. I exchanged my cable modem for a newer version at one of the TWCable offices - i think I have had it since 2006!
They have upgraded the TWC network here to handle the much faster speeds, so a newer modem was almost a requirement.
Still problems, so i began suspecting my DIR-655. I had a new drop from the telephone pole a few years back so that was my least concern.
Turns out my DIR-655 could not keep time! It could not get time sync from the internet

So I had it copy time from my PC - a day later it had hardly changed the time

Not good! If you know anything about TCP and packets and how routers everywhere work, you know that timekeeping is essential (hence NTP).
I am not sure this was a critical issue for my cable connection - I think the cable modem handles the essential timekeeping for that. But the lack of any kind of time keeping ability drove me to get a new router/switch/wireless - the new and improved Apple Airport Extreme 5th gen. I just wanted to eliminate the D-Link from this ugly problem I was having.
Still had problems even with the new router and new cable modem - it turns out I had problems in the back yard, the cable had gotten crimped from some construction apparently. I have a new drop and things are better, but I still have an issue. it appears to be under/inside the house so i will be getting a new outlet wired for the downstairs - upstairs seems fine, but downstairs is where the media/computing center is.
My brother-in-law agrees with many of you that D-Link is to be avoided, based on his work with routers/embedded systems and NTP a few years ago and some info he had read on D-Link issues. I will be searching for some of the documents he has read about issues with them. Kimchee411 I would be interested in any info you may have also. It's to bad, I really liked D-Links' style and other than the timekeeping I had no other issues with this DIR-655.
I will probably sell my Apple router once I have researched the newer generations of more configurable routers and when the new speeds become more standard.
By the way there is a very cool free app for iOS called Emerald Sequoia "Time"