Hmm. Yeah I have a spankin' new Intel Gig-E that was constantly disconnecting and reconnecting. The auto-negotiate in this router seems very sensitive and occasionally gets fubar. Like today, it wouldn't talk to my computer at all until I unplugged the cat 5 and moved it to a different port. Then, life was good again.
Now I have Intel -> Trendnet Gig-E Switch -> DLink and it's a little better. I think there are still periodic issues that I'm trying to work through, probably caused by some crappy Cat5 in my walls, but in general, the Trendnet is handling things better.
Given that the Trendnet switch cost 1/4 of the Dlink and my old router was 100x more reliable, I'm not sure why I don't just return the Dlink and go with old router + new switch. Oh well.