Just out of sheer frustration and endless problems, I'm driven to moan.
Why not bite the bullet and correct that top row spacing - you know the one I mean.
It makes prototyping a real pain in the backside.
I've tried all the workarounds, glueing extra headers on, bending pins and so on.
I thought the Uno and it's forerunners were all about giving folk an easy introduction to microcontrollers, not a re-engineering exercise.
Grateful as I am for the whole project, that one 0.06" error, late night, too many beers or whatever is destined to frustrate first-timers until the cows come home.
Words fail me.
I'm at a point where I want to move on and do some shields of my own, so it's either PCB's with the rotten spacing, or re-do the Uno.
Oh, and that's not to mention the huge grounded USB connector with all the shorting potential, and the not much smaller 2.1-mm socket - ever tried finding extra long header pins?
I love the "shields" concept, like mini Eurocards, but 0.06" gets in the way, every time.
Good night.
I think that 60mil was on purpose... That way you can't put on a shield the wrong way. Easy right?
And yeay, long headers are a pain. Just don't use them. Just use a separate footprint for male headers to the bottom and another separate footprint for female headers to the top and just offset them with 100mil
But whats wrong with the USB socket and 2,1mm socket?
You can't push a rope. 
septillion:
I think that 60mil was on purpose... That way you can't put on a shield the wrong way. Easy right?
No, they've admitted it was a mistake but the shield orientation benefit has been used as a justification for not fixing it. I refuse to buy an Uno because of the header spacing but the Pro Mini, Micro, and Nano are great little boards with standard pin spacing. I did buy a Mega 2560 when I first started with Arduino and the prototype shield boards make it usable.
If you're using shields, there is no problem. If you're not, why not put a standalone chip on a project board? That's what I do when I need a 'final' project. Putting an Uno in a project is a bit too costly and basically a waste of space/resources.
It would be cool if they use standard pin spacing but since they're not, there's a million ways to fix it.