One other option not mentioned here very often - mobile phone as a backup. This way you get mobility as well in case you need it.
1) can use build-in 56K modem (most of newer phones) with your existing dial up provider [the downside you use you plan minutes]
2) can use GPRS interned service pplan provided by cell phone company (T-Mobile charges 20$mo for unlimited access, they also have plan based on usage)