If you get ADSL you may have to buy an alternate modem which is a proper hardware one and Linux-compatible.
If you get Cable-Ethernet you should be OK. The superior Ethernet connection will depend on the ethernet driver in your computer. The other alternative, USB, can be more difficult, but the one supplied typically by NTL will work using the CDCether driver. But use the Ethernet if you can.
Asus Asus M2N32 WS Pro+Athlon AM2/4200+ â€” GeForce 7600GT â€” 2Gb Cosair VS RAM â€” 500Gb WD5000AAKS SATA Drive â€” PCLinuxOS