After much poking around the web to discover what the issue could be, I came across an interesting article that may have discovered the REASON and a SOLUTION (albeit not optimal):
The problem appears to be caused by an interaction with Bluetooth and specifically Bluetooth devices that use Advanced Audio Distribution Profile (A2DP) which is used to stream bluetooth audio from devices such as Bluetooth headsets and Bluetooth speakers.
The problem is caused when the Mac goes to sleep and wakes back up. It tries to connect to the A2DP device that was last used by the Mac. If that device is not powered on or is not in bluetooth range, it will keep trying to connect to that device (for an unknown amount of time). While it is looking for that Bluetooth device, the 802.11 wifi is also looking for the last wireless router or access point and fails to find it.
Why the wifi is unable to reconnect after waking from sleep is not exactly clear because wifi is a different protocol than Bluetooth. One hint is that it only seems to fail with wireless routers that run on the 2.4 Ghz band. That is the same frequency that Bluetooth uses (even though Bluetooth hops through different smaller bands within that frequency.)
The solution? Go delete your ~/Library/Preferences/com.apple.Bluetooth.plist file and reboot your mac. DON’T reconnect any speakers/headphones or anything that streams music to bluetooth. You CAN reconnect other peripherals such as a mouse/keyboard/trackpad and they will continue to work and not cause wifi issues.
So far (about 24 hours), this has worked like a treat for me, hope it works for everybody else too.
Here is the article that goes into more depth:
http://carnationsoftware.com/LastA2DPDevice_Mac_Wireless_Problem.html