Going to have a dedicated line installed- What should i know to ask for?

I had a great electrical contractor in Brooklyn when I lived there- sadly, he is in prison for life. When I saw the NY Post article about it (I had moved up to the Lower Hudson Valley by that point), I told my wife, "I’m tempted to go to court as a character witness. And say, ’Look judge, I know the guy was convicted or plead out to some really bad stuff, murder, embezzlement, money laundering, kickbacks, obstruction, etc. but you gotta realize, this guy was an unbelievably good contractor. You know how hard those are to find?"
You’ll be in good hands with @jea48 and some of the others here who really know their stuff.
A dedicated line will not isolate you from electrical gremlins within a system that shares ground with other stuff, even within a private house. It is still a good idea, if only to get a new fresh run, unencumbered by other appliances or connections. That does sound cheap, even by the standards of the guys with, ahem, you know, good connections? :)
good luck,

@jwolchak- I'm not sure that's true. For a residential application the iso transformer would have to be tied back to the main electrical system ground. (You cannot float the ground on the secondary, as I understand it, or ground to a different grounding point without violating Code, at least in the States). 
It will nonetheless isolate from certain things, but not everything. I'm currently using a large 10kVa isolation transformer from Controlled Power with a high K rating between the panel and subpanel for my system and it's great; the unit, which is large at 400+pounds, is installed in a weatherproof cabinet outside.
This is a more standard EI type, not a toroid. I'm a pretty big fan of iso transformers.
I've encountered different meanings for 'fully or completely isolated' in this context- some see a completely separate ground as essential but I don't think it is possible to do for a residence and stay within Code. (I'm not a Code expert or electrician, just used these things and dealt with their installation). Others here with a working knowledge of Code could amplify or correct any misstatement on my part. 
Welcome to the 'Gon.