I also favour good ol' external Serial port modems (USB are as basd as Windmodem, just use a damn COM port already )
Easier to configure, less problems, and no WinModems. They are also more O/S friendly
Just make sure your Serial ports have 16550 UART controller behind them If you only have an 8550 you won't be able to get 56k speed out of them *laughing*
(in case you have no idea what I'm talking about, don't worry about it, my 486 motherboard had a 16550 UART chip, I don't know what board you have, but any board that supports a P3-866 will have a 16550 UART)