You've probably already decided whether you want an electric range or gas, though you did not say in your post, so if you haven't you'll want to think about that. You'll also want to consider whether you want the oven to be convection or not.
As far as deciding between 4 or 6 burners, it really all depends on how much extra money you are willing to pay for it. Having 2 extra burners can be nice but if you think you will not be using them very often it may not be worth it. and there will also be a small sacrifice in counter space with a 36".

I would go with a 30" NXR, can get one for $2000 delivered to the door, fits everything you are looking for so you can spend the other $1500 of something else.

Since you said you are completely renovating, have you considered a rangetop and separate wall ovens? I realize it would be over your budget, so I am just asking you to think about it in the scheme of your total renovation, and your cooking needs. The reason I am suggesting this, is that I chose a 30" range due to budget considerations, and have been kicking myself ever since. I should have found the money from somewhere else in the kitchen, because the 30" range with its single oven has not been adequate for my family. And don't even get me started about holidays.

You could get a 36" rangetop with 6 burners which gives you the extra real estate for pots and landing space. Meanwhile you wouldn't have to deal with the pre-heat times of the large 36" oven, especially if, say, you are just heating up a small casserole or something. Plus, no bending with wall ovens. Plus, if you get double wall ovens, you could bake two different things at once that need different temperatures. That's been my issue; no way to cook two different things in the oven. We have an advantium, but it just doesn't work as well as if we'd chosen two wall ovens. Just my $.02. We were on a tight budget, but I think we should have explored a way to afford the range top and separate wall ovens. Don't mean to be presumptuous about your budget; only trying to relate my experience.

I'm with shannonplus2, for all the same reasons. I like the versatility of a cooktop and double wall oven. But it depends, of course, on how you use your kitchen, so a range may still be best for you. Does the 36" range have a double oven?

And I'm assuming that you have definitely ruled out induction? I mention it only because it is safer around kids. Also, the induction cooktop, being flat, doubles as temporary counter space, so you don't lose much if you go up to 36".

There is no evidence to prove induction is superior to gas for children's safety. Thread below on topic.

http://ths.gardenweb.com/forums/load/kitchbath/msg031539215604.html?2

Below is a floor model Bluestar RNB in slate gray for $3500.

Flat out superior to what you are considering.

Here is a link that might be useful: Bluestar LINK