|Well, with 2 different routers having the same issue - it doesn't sound like the routers fault...?|
Try to isolate the issue:
1) Install Wireshark
2) Start wireshark, under 'Capture filter' type in: 'port <port number>' (like: 'port 80')
3) Select your Network card under the capture interface (at the top) and click 'Start'
4) Wireshark is now capturing traffic - go do another port test
5) Stop the capture (click stop)
If you see SYN's coming into your machine, then the port forwarding is working fine (it's not the router's fault)
Sorry, not much help from there, but the above test should determine if the issue lies w/ the router or the computer - post your results.