In New Zealand the most common type of internet connection is an ADSL modem.
What is the most common type of connection in your country?
I think for most of the world the most common broadband internet types would be either DOCSIS (Cable) or DSL technology (remember these are ADSL, VDSL, SDSL etc). However I feel this will decline in the near future as the world moves towards Fibre to the Home, and more stable high speed Wireless technologies (such as LTE or WiMAX).
I wouldn't find it surprising to find that Dial Up is quite popular, especially in developing nations where broadband infrastructure does not exist, or is too expensive.
Like Possum, I am also from New Zealand. My internet speed here varies, but is usually around 9Mbps Down and 0.6Mbps Up with about a 25ms ping time.
Most of America (at least the more populated areas) have cable (I think Comcast is using DOCSIS 3 now) or fiberoptic, although I know there are still plenty of rural areas that can only get dial up or DSL.