It goes well with both navy and gray, and it hasn’t been in for long enough that you probably don’t own anything that color. I think that the dark orangey-red family of colors, usually called rust, are in for a resurgence over the next couple of years. If you buy rust now, it should look current ’til at least 2009, depending on where you live.
I created a palette over at ColourLovers to show how rust might work with possible fall colors. If you click on this palette, you may notice I named the color in the middle “oxidized.” I think the color name “rust” has too many negative associations for people. You’ll probably see it called “bittersweet” or “blood orange” or “cinnabar.” Post your own suggestions for rusty pseudonyms in the comments!