Fast forward to a few days ago and...well, BUFFALO happened. What a piece of S**T. And I'm not the only one that has issues with it.
[Edit: Please try the port forwarding first with the original firmware before attempting this as you may be one of the lucky ones and have it work right out of the box.]
If you need it to ONLY use the internet and do absolutely NOTHING else...then it's for you. But if you do anything else well you need to modify it and yes...break your warranty. I didn't care about that! I just wanted the port forwarding to work! And if you do too...these are the steps I took and I hope I don't leave anything out.
***Step 1a is if you haven't changed the firmware yet...if you have been mucking with dd-wrt already, go to Step 1b.***
Get rid of the stupid OEM firmware and get DD-WRT installed. (Just so you know I installed DD-WRT and port forwarding didn't work right away. If yours did then you suck =p ). You can follow these instructions from HERE to get dd-wrt installed. Then once you've upgraded to the latest firmware, changed the username and password...
(Step 1b. - If you do Step 1a skip this one.
So you already have it installed and been pulling your hair out trying to get port forwarding working but it just won't go...well this is EXACTLY what I did. I got OpenWRT's upgrade file from here and get openwrt-ar71xx-generic-whr-g301n-squashfs-factory.bin (maybe you don't have to but this is how I got mine to work...) then do a firmware upgrade and select "Reset to default settings" and start over (actually it didn't install OpenWRT but it was one of the steps I did to get it working. It's highly possible you just need to reset to "factory defaults".)...see step 2)
DON'T click on "Apply Settings" AT ALL until you finish EVERYTHING! even the port forwarding lines.
Instead click on "Save" for each page/change you make.
These are the lines I put in my NAT->Port Range Forwarding. I have 6 lines...just click add 6 times and then enter your info (IP Address of course should be changed to YOUR server IP).
Application start end Protocol IP Address Enable
1 1 138 Both 192.168.0.100 "checked"
2 140 444 Both 192.168.0.100 "checked"
3 446 630 Both 192.168.0.100 "checked"
4 632 8079 Both 192.168.0.100 "checked"
5 8081 22272 Both 192.168.0.100 "checked"
6 2274 65535 Both 192.168.0.100 "checked"
of course you could change the lines to whatever you wish...but with one line from 1 to 65535 didn't work initially for me but that was before I started over. It might work for you.
After I went thru every single tab and option that I needed, I finally clicked on "Apply Settings" while in the Administration->Management tab. Next I clicked on "Reboot Router". I also rebooted my ISP's equipment...Then I waited and got online and crossed my fingers. Using THIS link (Open ports checker) I did what I did MANY times and clicked on check common links at the right (near the bottom)....and oh the sight of the green flags were amazing =) FINALLY!!! it works!
Hope this wasn't a fluke and that it helps SOMEONE out there!