Well, If you use DSL as-is, and tried some drastic data exchange - you could get extra lag or problems. I can't believe this link is still alive;
http://cable-dsl.home.att.net/
This is where I got my first "tutorial" on DSL - lots of valid info there.
Also at this link;
http://www.speedguide.net/
there's a "TCPOptimizer" tool that I have been using for years on windows machines - works very well.
When I played EQ live, I read on their Faqs that "ping" was very important (latency), if you had a slow ping, then you would have lag in game.
I have been to places where internet, no matter what you have - is not worth a rat's ass.
I was thinking; why not have the zones spread out over different servers at different locations? I mean, like x amount of zones here, another amount at GeorgeS, John Adams, and anyone else who wants to be in on it.