Not a typical limit but can often be a limitation in certain areas. My parents have ~220kb/s down, 70kb/s up due to poor quality wiring and being far from the exchange. Most UK cities are reasonable, but go out to the smaller areas with only ADSL and it goes to all hell.

Not really, I am running Virgin Media and get a 60mb/s line for £24.99 / month including a phone, I've clocked it at around 43mb/s download and 4mb/s upload, the upload is still fairly abysmal, but it's enough for home usage.