The D2 works fine with any router capapble of port range forwarding or has a DMZ
if your LAN is configured statically (which it is not for most "plug and play" router users, one must read manuals and understand basic networking concepts to configure a LAN statically, which is much rarer than you'd think), and if you disable UPnP, allow pings from the WAN and disable built in firewalls. However this is pretty much beyond most users. (there is something drastically worng with the router market, if I could solve it I'd be rich). I think the growing problem relates to the desire for wireless home LANs so that routers are far more popular than they used to be and in the hands of people who do not really know how to use them. (Not to mention the whole issue of wireless unreliability...)
Linksys, USR, Dlink, Zyxel... they all work. PEBKC.
As I mentioned above, it is probably easiest to bypass the router altogether if you want to play on the D2. That way you do not have to think about it. (except you may have to release the WAN DHCP lease at the router before attempting to obtain one for your PC's network card, depending on your ISPs DHCP server configuration).
Hmmm... maybe its time I started developing the "NetMagic" box... a router for the masses. It will do everyhting for you, make coffee, play My Melancholy Baby and automatically configure your entire network constantly anticipating your every need...
Seriously.