Ask HN: How important are ergonomics to you?

In an never ending race to improve myself and my productivity i also think alot about the perfect hardware, software and enviroment. I bet many of you do aswell. I probably think way to much about this which isnt good for my productivity in the first place, just like surfing on HN and similar sites, but have to do what it takes to feel comfortable.

I currently use a pretty powerful Windows 7 box with Dual 24" Dell IPS Screens. In ergonomic terms, this is very good.

* Both displays have the same size, resolution and DPI

* Both screens upper corner is where my eyes look at when i sit in front of it comfortably

* Both screens are about an arm length away

* i can move the keyboard around

* my chair is prolly not perfect, but i dont have the money for one of those airon chairs yet

Sitting in front of this setup all day, i feel its important to think about such stuff. Yet i see alot of people here or elsewhere (like Facebook or other startup) offices that work from a Laptop all day which is something i think about doing since i hate syncing my workspace data and logins/bookmarks etc on seperate machines. So i find the thought of having everything i work on with me all the time very compelling. I also want to change back to Mac only (i had a MBP last year), just so you know.

The drawbacks of this approach for me:

* i am used to having 2 large Displays for years, will a Laptop + external screen hinder my productivity (although the latest 15" MBPs have a 1680x1050 resoultion which is almost the res of my Dells)

* a Laptop + external screen have hugely different size and DPI, which is not ergonomic

* plugging in all the external stuff all the time if i want to show something to somebody or stuff like that speaks against a Laptop only solution and for something like a mac mini + 2 displays and a macbook air 13". Best of both worlds basically, but again the need to discipline yourself and sync all the relevant data to have everything in place

So id like to know what the folks here think about that, as i just cant decide on whether to go with a 15" MBP for everything or a 13" Air + mac mini/pro. I dont like iMacs, having them with a second screen doesnt really fit, glossy displays arent ergonomical and MBP + external screen does the same for me.

thanks in advance. Now i should prolly get back to work ;)