Socket wise, I went with 8, 10, 12, 14, 15, 17, 19, 21, 22, and 24. The 21 mm with a breaker bar will work in a pinch on the lug nuts. Your lug nuts might be 19mm, which is the lug nut size of my work Explorer (actually 3/4", I'm sure, but those two sizes are interchangeable). Unlike some, I always carry the factory lug wrench, since I'd prefer not to stand on my breaker bar and socket just to change a tire.
Don't forget a spark plug socket, and if you're the kind of guy who likes to carry a front cv axle, you'll need a big 12 point socket (the early Tundras are 36mm, the new Tundras are 39mm). I'm not sure about your FJ, but I'd strongly suspect it's 36mm. I don't own one of those sized sockets (you can rent them or borrow them at parts stores), but if I do buy one, I'm going to get one for an impact wrench.
That's what I've come up with so far, I'm still tweaking my setup. I've bought a few more tools recently.
By the way, these are just the hand tools. I also keep a recovery kit, jumper cables, a 48" hi-lift, an axe, a Wyoming saw, an MV-50 air compressor, and several flashlights stashed within various parts of the rig.