I was just going to suggest upgrading glass first.
That Canon lens would set you back almost as much as the 70D body, but between the constant 2.8 and the IS, I think it's a lot more bang for the buck. My problem is that I already have that lens and don't really have a next step without moving to FF, which just isn't happening any time soon.
There are some cheaper alternatives, like the Tamon 17-50 2.8. I didn't love it when I had it for Sony, but it's still a big upgrade over a kit lens.
So you have an upgrade itch, but don't know where to focus? Your software needs are all met? Lighting?
I try to resist body-upgrade itches, knowing that there will always be a newer better body every year or so. Right now, I am tempted to upgrade from my Sony A55 to A77... but I'm waiting, to see if the next model is more compelling. An upgrade now, wouldn't really do anything for my IQ except for higher resolution. So do I upgrade just for a better body, better AF, and higher resolution...
Do I save my pennies for FF.. do I wait another year or 2 for more APS-C advances...
It's hard to know *when* to pull the trigger. But I try to be patient.