I've read through some of the threads here but didn't find anyone have the same issue, so I thought I would throw my issue out to the smart folks instead of 1) boxing and returning or 2) picking up a hammer...
I purchased the DGL-5500 from New Egg and it works...just not consistently or for more than a few hours at a time. I have never have an 'up-time' of more than four hours before it drops the IP; sometimes it only lasts an hour. It drops (regardless where I use static or dynamic) but ALWAYS immediately re-obtains an IP and continues to resume connection. I upgraded to the newest firmware and have contacted the ISP about the line (which is new) and they modem (which is also new) and they found no issues. I have played around with a few settings over the last couple of days and nothing I've tried has helped. I only have two items hardwired (a PC and an Xbox) and have an iPhone on 2.4GHz (5Ghz turned off). 
The logs below are from a reboot of the router captured at start up. You will not the time change randomly in the logs; its weird but it always eventually reverts to the correct time. I will attempt to catch the logs of the random disconnects when it occurs. Please let me know what other information might be useful to have to assist with identifying the problem. And yes, I intentionally added ".xx" to mask my true IP for those you smart-a$$es like me that would chime in and say "well, there's your problem" 

I really do appreciate any and all advice and assistance.
Nov 1 18:10:39    UDHCPD Inform: add_lease 192.168.0.100 
Nov 1 17:10:25    Service D-Link HNAP Service (/var/etc/avahi/services/dhnap.service) successfully established. 
Nov 1 17:10:25    Service D-Link DGL-5500A1 (/var/etc/avahi/services/mtdaap.service) successfully established. 
Nov 1 17:10:24    Server startup complete. Host name is dlinkrouter.local. Local service cookie is 4204617028. 
Nov 1 17:10:23    Registering new address record for 192.168.0.1 on br0.*. 
Nov 1 17:10:23    Registering new address record for 192.168.0.1 on br0.*. 
Nov 1 17:10:23    Registering new address record for fe80::7a54:2eff:fe11:d298 on br0.*. 
Nov 1 17:10:23    Registering new address record for fe80::7a54:2eff:fe11:d298 on br0.*. 
Nov 1 17:10:23    Network interface enumeration completed. 
Nov 1 17:10:23    New relevant interface br0.IPv4 for mDNS. 
Nov 1 17:10:23    Joining mDNS multicast group on interface br0.IPv4 with address 192.168.0.1. 
Nov 1 17:10:23    New relevant interface br0.IPv6 for mDNS. 
Nov 1 17:10:23    Joining mDNS multicast group on interface br0.IPv6 with address fe80::7a54:2eff:fe11:d298. 
Nov 1 17:10:23    Loading service file /var/etc/avahi/services/mtdaap.service. 
Nov 1 17:10:23    Loading service file /var/etc/avahi/services/http.service. 
Nov 1 17:10:23    Loading service file /var/etc/avahi/services/dhnap.service. 
Nov 1 17:10:23    avahi-daemon 0.6.30 starting up. 
Nov 1 17:10:23    Successfully dropped root privileges. 
Nov 1 17:10:23    Found user 'root' (UID 0) and group 'root' (GID 0). 
Nov 1 17:10:22    Current local time and date: Fri Nov 1 17:10:22 2013 
Nov 1 18:10:22    read /etc/hosts - 3 addresses 
Nov 1 18:10:22    using nameserver 75.75.75.75#53 
Nov 1 18:10:22    using nameserver 75.75.76.76#53 
Nov 1 18:10:22    reading /etc/resolv.conf 
Nov 1 18:10:22    compile time options: IPv6 GNU-getopt no-ISC-leasefile no-DBus no-I18N no-TFTP 
Nov 1 18:10:22    started, version 2.41 cachesize 150 
Nov 1 18:10:21    device_lan_ip=192.168.0.1 , device_lan_subnet_mask=255.255.255.0 
Nov 1 18:10:21    DHCP server start. 
Nov 1 18:10:19    avahi-daemon 0.6.30 exiting. 
Nov 1 18:10:19    Leaving mDNS multicast group on interface br0.IPv4 with address 192.168.0.1. 
Nov 1 18:10:19    Leaving mDNS multicast group on interface br0.IPv6 with address fe80::7a54:2eff:fe11:d298. 
Nov 1 18:10:19    Got SIGTERM, quitting. 
Nov 1 18:10:19    exiting on receipt of SIGTERM 
Nov 1 18:10:18    Aperture turned off 
Nov 1 18:10:18    ozKer: (INFO): Parent process exiting. 
Nov 1 18:10:18    ozKer: (INFO): Listening on 127.0.0.1:9000 
Nov 1 18:10:18    ozKer: (INFO): Running as daemon 
Nov 1 18:10:18    (NOTICE): policy_engine: output pipe ok: /var/run/appflow/tccpipe 
Nov 1 18:10:18    (NOTICE): input pipe ok: /var/run/appflow/drflocs_out 
Nov 1 18:10:12    (NOTICE): Local Net: 192.168.0.0 / 255.255.255.0 
Nov 1 18:10:11    (NOTICE): Policy Engine Start 
Nov 1 18:10:11    bwcd start complete 
Nov 1 18:10:11    bwcd starting 
Nov 1 18:09:49    streamboost update 
Nov 1 18:09:49    StreamBoost: Executing boot all 
Nov 1 18:09:48    crond 2.3.2 dillon, started, log level 8 
Nov 1 18:09:47    version 1.8.3 started 
Nov 1 17:09:45    Service D-Link HNAP Service (/var/etc/avahi/services/dhnap.service) successfully established. 
Nov 1 17:09:45    Service D-Link DGL-5500A1 (/var/etc/avahi/services/mtdaap.service) successfully established. 
Nov 1 17:09:44    Got SIGHUP, reloading. 
Nov 1 17:09:44    Service group file /var/etc/avahi/services/dhnap.service changed, reloading. 
Nov 1 17:09:44    Files changed, reloading. 
Nov 1 17:09:44    Service group file /var/etc/avahi/services/mtdaap.service changed, reloading. 
Nov 1 17:09:44    Files changed, reloading. 
Nov 1 17:09:44    Service group file /var/etc/avahi/services/http.service changed, reloading. 
Nov 1 17:09:44    Files changed, reloading. 
Nov 1 17:09:44    Files changed, reloading. 
Nov 1 17:09:44    Service D-Link HNAP Service (/var/etc/avahi/services/dhnap.service) successfully established. 
Nov 1 17:09:44    Service D-Link DGL-5500A1 (/var/etc/avahi/services/mtdaap.service) successfully established. 
Nov 1 17:09:43    HTTP listening on port 65530 
Nov 1 17:09:43    Server startup complete. Host name is dlinkrouter.local. Local service cookie is 2322130758. 
Nov 1 17:09:42    disable write rom conf. 
Nov 1 17:09:42    Registering new address record for 192.168.0.1 on br0.*. 
Nov 1 17:09:42    Registering new address record for 192.168.0.1 on br0.*. 
Nov 1 17:09:42    Registering new address record for fe80::7a54:2eff:fe11:d298 on br0.*. 
Nov 1 17:09:42    Registering new address record for fe80::7a54:2eff:fe11:d298 on br0.*. 
Nov 1 17:09:42    Network interface enumeration completed. 
Nov 1 17:09:42    New relevant interface br0.IPv4 for mDNS. 
Nov 1 17:09:42    Joining mDNS multicast group on interface br0.IPv4 with address 192.168.0.1. 
Nov 1 17:09:42    New relevant interface br0.IPv6 for mDNS. 
Nov 1 17:09:42    Joining mDNS multicast group on interface br0.IPv6 with address fe80::7a54:2eff:fe11:d298. 
Nov 1 17:09:42    Loading service file /var/etc/avahi/services/mtdaap.service. 
Nov 1 17:09:42    Loading service file /var/etc/avahi/services/http.service. 
Nov 1 17:09:42    Loading service file /var/etc/avahi/services/dhnap.service. 
Nov 1 17:09:42    avahi-daemon 0.6.30 starting up. 
Nov 1 17:09:42    Successfully dropped root privileges. 
Nov 1 17:09:42    Found user 'root' (UID 0) and group 'root' (GID 0). 
Nov 1 17:09:41    Current local time and date: Fri Nov 1 17:09:41 2013 
Oct 23 12:25:14    read /etc/hosts - 3 addresses 
Oct 23 12:25:14    using nameserver 75.75.75.75#53 
Oct 23 12:25:14    using nameserver 75.75.76.76#53 
Oct 23 12:25:14    reading /etc/resolv.conf 
Oct 23 12:25:14    compile time options: IPv6 GNU-getopt no-ISC-leasefile no-DBus no-I18N no-TFTP 
Oct 23 12:25:14    started, version 2.41 cachesize 150 
Oct 23 12:25:10    wantimer: [Cable Connect, No IP]-'[Cable Connect, Have IP] 
Oct 23 12:25:09    UDHCPD Inform: add_lease 192.168.0.100 
Oct 23 12:25:08    start wantimer 
Oct 23 12:25:04    Lease of 69.140.181.XX obtained, lease time 304286 
Oct 23 12:25:04    Sending discover... 
Oct 23 12:25:04    device_lan_ip=192.168.0.1 , device_lan_subnet_mask=255.255.255.0 
Oct 23 12:25:04    DHCP server start. 
Oct 23 12:25:03    DHCP client start. 
Oct 23 12:25:03    User config file /var/run/appflow/streamboost.user.conf does not exist, exiting 
Oct 23 12:25:02    [Initialized, firmware version: 1.11 ] 
Oct 23 12:25:00    0x000000fe0000-0x000000ff0000 : MAC 
Oct 23 12:25:00    0x000000f60000-0x000000fe0000 : My-Dlink 
Oct 23 12:25:00    0x000000f30000-0x000000f60000 : LANG 
Oct 23 12:25:00    0x000000040000-0x000000f30000 : linux 
Oct 23 12:25:00    0x000000030000-0x000000040000 : nvram 
Oct 23 12:25:00    ath-nor0 
Oct 23 12:25:00    klogd started: BusyBox v1.01 (2013.10.23-06:36+0000)