Either camera will be a nice upgrade for you...
Higher ISO... about one full stop on average.
The AF of the 60D would be pretty similar to your 40D's. The AF of the 7D can be better, used right. For example, the above user states he's using Spot AF mode for birds.... Well if the birds are roosting on a branch, that's fine, it's a good choice... But if they're in flight, wrong! It's slower than standard size focus points. Canon doesn't recommend Spot AF for moving subjects.
I tend to use Single Point AF most of the time, along with Back Button Focusing and AI Servo. The 7D gives you more AF points to choose, 19 vs 9 in the 60D. They are all "cross-type" in both cameras, same as your 40D.
But, honestly, with 50D and 30D before that, using similar AF techniques, I could consistently get acceptibly accurate focus in 95 or 96 out of every 100 shots. Now with 7D, which is better tracking movement, I can nail 97-98 out of every 100. Better? Yes. Huge difference? No. If used properly, the "lesser" cameras are pretty darned capable.
The 7D's active matrix/transmissive LCD viewfinder takes some getting used to, especially for AI Servo shooters. There's no red flash of the active AF point when AF starts, the way there is in the cameras with the simpler system (such as the 60D). Instead, the camera only displays the active AF point(s), as a gray box. (Note: you can set it to display all points, all the time, but I don't know why you would want to do that). One Shot is different... where your 40D flashes the AF point red to give Focus Confirmation... 7D flashes the entire display (if you have this enabled).
7D is the "ultimate" camera for your purposes, short of going to a more expensive 1D series. It is more complex and harder to learn to use well than 60D (which should be pretty easy, coming from a 40D). The 7D is more customizable, can be fine tuned more for specific situations. Those features can give you that last little bit of an edge when used right... or make your keeper rate drop like a rock, if used wrong.
The 7D is also heaver and built to be a bit more durable (150,000 click shutter, vs 100K in 40D and 60D), a little better sealed. 7D has metal clad body, more simlar to your 40D. 60D uses more polycarbonates (aka "plastic"), which allows it to be lighter.
The 60D has that neat articulated LCD screen, which might be handy for macro, landscape shooters, and especially for videos.
7D has "Micro Adjust" to fine tune focus on a lens by lens basis. 60D doesn't have that.
7D has a 100% viewfinder... nice! But that's probably a big part of the reason it weighs so much (it's actually slightly heavier than 5DII). The 60D has a more typical, 96% viewfinder. Not bad, really.
Control layout of 60D is a bit different than 40D or 7D. Might take a little getting used to.
Either camera uses pretty much the same sensor and processing. If you shoot and work with RAW files, you should expect to have to sharpen your images considerably more than you do with 40D. In addition to the much higher resolution, both cameras use a stronger anti-alias filter, so RAW files straight from the camera appear a bit soft... but sharpen up nicely.
Also, if you are a pixel peeper with your 40D, often lookng at your images at 100% magnification on your computer monitor... beware! With almost twice the resolution, using the same magnification on the images out of either 60D or 7D will be like lookng at your images nearly twice as critically, nearly twice as large.
Because of the very high resolution of these cameras, some folks think these cameras are more sensitive to even slight camera shake. I just make a habit of using a slightly higher ISO than I did with previous cameras, to insure a slightly higher shutter speed. Where I used ISO 100 and 200 by default before, now I use 200 and 400, even in good daylight. It's not a big deal, just "different". Canon has a white paper about it, on their website.
Is it worth it to you, considering the extra cost, for 7D? Only you can say. Either camera can take great pics and serve you well!