For me, very good quality and reliable connections are the primary considerations aside a sufficient speed (which at the moment is 1m

)
Since alot of my traffic goes to outside Finland, mostly to europe and US, the ISP must be one with good routers to europe and US.
For that, I'm not quite confident with the cable modems, which with you're pretty much gambling whether you get a good one or bad one - as the cable modem ISP's and the areas can vary alot in the quality of connection.
So an ADSL, which is available aside a cable modem, is my choice..