I get 10.0MB/sec (80Mbps) with netcps. This was between:
400Mhz Celeron, 224MB RAM, WinME
800Mhz P3, 512MB RAM, Win2000
both w/ 3c905b's - latest drivers running through a cheap-o Addtron 5-port switch.
Another program I use is iperf. It allows you to play with TCP windows sizes, use UDP...