Hi Mashrok, and
to CF!
1. New ntl broadband installations use an ntl:250 Cable Modem made by a company called Ambit. It has both USB and Ethernet connections.
2. 12 months is the minimum contract. You're free to leave any time after that with 30 days notice.
3. In my experience, most routers are much the same when it comes to signal range. I'm sure others can help you more on this subject though as I don't use wireless regularly at home!
4. It's entirely true for the moment! There's no hard-and-fast limit on how much you can download/upload via an ntl broadband connection. However, it is subject to Fair Use, so if your usage starts to impact on other customers your connection might be restricted (to a slower speed, for example).
Hope this helps!