Satellite has improved it's latency somewhat. I think at good times it's around 900ms, which I've played for 4 yrs on dial-up averaging that.
However since Wotlk has come out dial-up latency is really killing me especially tanking. I'm having troubles keeping threat built up as there is a delay between instant cast spells at times of 3-4 seconds. Which for myself the main problem is the limited bandwidth available with dial-up which will not be an issue with satellite.
Have you considered wireless internet through your cell phone company, I know Verizon/Alltel offer it here between $59-69 a month with comparable speeds and ping times to DSL. It essentially means plugging a mini-antenna into your USB port and playing that way. I've considered it myself but I can't afford $69 a month right now or the foreseeable future. However I think satellite runs between $69-99 a month plus whatever installation costs are, it may be an option worth looking into.