Hi, Element14. First off, let me tell you how much I like Eagle. I bought version 4 back in 2001 for $1212. (Schematic editor, pcb layout and auto-router - woo hoo! Times were good.) Then in 2004, I upgraded to V4.1 for $315. (I don't know why I had to pay for a minor release, but there you go.) Finally, I went to V5 in 2009 for $400. I've never regretted my choice - over the years, Eagle has gotten better and better and my total outlay is still less than $2000. I can hardly get a schematic editor in one of the major CAD packages for that.
But I haven't made the move to V6. The price tag for me is around $600 and for that I get two new features: differential trace routing and design files stored as XML. Diff traces would be nice, and I guess XML files will be great once people create some cool tools for processing them. But to me, it's not a lot for $600. (Not that I begrudge you the right to profit from providing an excellent tool.) But more than the price, the main reason I'm not upgrading is because Eagle is isolating me from the community.