Dell does hardware, so do hardware.
* There are many good stuff & dev tools packaged or installable within Ubuntu. Don't try to mimic that. For example, for Ruby, I use RVM to manage it, not the package from Ubuntu. Software or dev tools are not the point.
* Ubuntu should be installable from a generic Ubuntu ISO on the laptop.
* if there are needs for specific drivers, fine. Go upstream, submit to kernel or whatever else. Don't provide bloat stuff. ATI propriatory linux driver don't support the choosen GC, step into the breach, call them, make them update their driver. Your hotkeys (volume....) doesn't work out of the box, find the right place and submit a patch. Everything have to work Out Of The Box, with a "legacy" Ubuntu.
* No troll between Unity/Gnome/KDE : if any generic Ubuntu ISO can be installed, there is no subject for that.
And then, concentrate on hardware. What a good laptop for dev could be ?
Laptop mobility :
* Matte screen : for use outdoor or in sunny place. (we are not in a mall, a bright screen only purpose is to attrack people, but that does suxx)
* Battery life : 6 hour is a vital minimum.
* a 13"/14" screen : Dev often use a 20" to 24" secondary screen for confort. It'd be nice to have a real mobile laptop.
Others parts :
* Keyboard : they are vital keys. I remember a Dell Vostro with no direct Home key, nor End. In order to go to the begining of a line, doing Fn+any_other_key is wrong. A dev writes code. A adequate keyboard should be thought.
* Numerous USB port : less than 4 is a non sense. 2 near the front, and 4 in the back would be a good design.
* CPU : provide a choice : from Core i3 to Core i7
* RAM : idem : from 4Go to 16Go
* Storage : idem : a choice between SSD or HDD
=> not every dev have the same needs or budget. Offer a choice.
I can sum up :
* A real Ubuntu working out of the box without specific things to install.
* Matte screen
* A real keyboard