what adsl modem?

have just got an airport extreme base station, and want to connect to broadband internet via it. my current asdl modem connects via a usb, so realise I need to buy an ethernet port modem before I can use it. just read reviews of various modems, including apples favoured d-link dsl-300t and convinced myself the outlook is very bleak. any advice on what to buy would be great. thanks.

i-mac 1GHZ PowerPC G4 Mac OS X (10.4.4)