Ethernet is spec’d to go up to 100 meters without problems on the proper cabling. On good cables it’ll go further than that before you get dropped packets. You can extend it even further by putting a switch or repeater in the middle, or by using fiber optic ethernet which can go several miles.
The phone cabling for ADSL can go typically 3-5 miles depending on the type of technology used, sometimes further for newer stuff. The problem is that it needs twisted pair cabling, while most inside phone extension cables have untwisted cabling. If the cable is round it is probable twisted and if it is flat it is untwisted. High frequency signals degrade over untwisted cabling pretty quickly, so if you want to extend ADSL lines a good distance you should only use twisted pair cabling. The alternative is to put the ADSL modem near the jack and run ethernet out to the computers.
As for the poll, I’m happily on So-net for a couple of years now and the performance is always very good for me, even for VOIP. I’m currently at 2m/512k service. The only problem has cropped up in the last couple of months. Some p2p networks are banning So-net connections because the ISP is owned by Sony and they are afraid we’re all piracy cops. Oddly enough even p2p sites that appear to only have legal content use that blacklist! Unfortunately even more sites block Hinet because of hacking, open proxies, spammers, etc. and there’s plenty of other p2p networks that don’t block So-net.