Well, I work in the industry, actually working for a local Brisbane ISP. I wouldn't touch a Billion if you paid me. What do you need the modem to do? How many Ethernet ports will it require (i.e. how many computers will be connected to it)? Will it require Wireless? ECN can do both phones and ADSL2+, although I cannot guarantee ADSL2+ due to a variety of issues. The best way to see is to place an order and see what happens. PM me with your fnn (phone number) and I'll be happy to do a SQ test for you (rough test to see if the number is eligible for an ADSL service). Our pricing can be found at the following 2 links for both ADSL and ADSL2+.
http://www.ecn.net.au/forms_v2/Broadband%20Now!%20Powernet%20Appli cation%20National.pdf
and
http://www.ecn.net.au/forms_v2/Power...0Agreement.pdf
I don't do a lot with the ADSL, my specialty area is with the web hosting and Hosted Exchange, but I'll be only too happy to answer any questions that you might have.
Cheers,
Dave
edit: don't use USB as others have said. Use Ethernet. USB requires the installation of USB drivers for the modem, Ethernet requires no drivers and is far more reliable from my experience. I'd recommend a Netcomm NB6, or if you require more Ethernet ports and maybe Wireless (good idea for future proofing imho), I'd recommend the Netgear DG834G (or the newer DG834N).