I'd still shoot Kodachrome. As you say, Kodachrome's reds, oranges, and yellows make it one of the best choices out there for fall colors. Also, if you are shooting fall colors at high altitude (like California's Eastern Sierra or the Colorado Rockies), Kodachrome gives a REALLY nice dark, navy blue sky like no other film can. This makes a most excellent backdrop to the mountains and changing leaves.
Originally Posted by nickrapak
Aesthetic qualities aside, I can think of one more reason to shoot Kodachrome rather than something else. Velvia, Provia, Ektar, Portra, and all those other E6 and C41 films will most likely be around in a couple of years. Kodachrome WON'T. If you don't shoot it this fall or next, you will NEVER be able to shoot the fall colors with it. And, if anything, it will probably be harder to get a year from now. So shoot it now while you still have the chance.