I was deciding between D90, D7000 and 60D just last month. I have a Canon 28-80 and Sigma 24-70 (Nikon mount) so I was looking at a new body only.
I went to Henyrs to try them out and 60D didn't impress me at all. The camera doesn't feel as sturdy as D90 and D7000, probably because of the flip-out screen. It may be a good feature when taking video but I can't image what would happen if the camera is dropped while the screen is in the "out" position. I don't like the control layout too, everytime I try to press the multi-way controller at the back, my thumb scroll the control dial.
Between D90 and D7000, the later feels more sturdy probably because of the weather sealed metal housing. Beside build quality, AF is a difinitely faster and the dynamic range provided by D7000's sensor (made by Sony) is way ahead than Canon offerings in this price range.
D7000 is the best choice for me, even though it is almost $200 more expensive than 60D, D7000 represents more value in my opinion. I'd also suggest you to try them yourself, you might find 60D more comfortable if you have bigger hands. Beside camera bodies, take a look at lenses, flashes and other accessories which you're most likely to buy from both Nikon and Canon. Look at the system as a whole offered by both compaines.