Edgar Ironpelt
Adventurer
I'm running 3.5e, and I let rangers take a feat instead of an animal companion. In fact, in my Brotherhood of Rangers game (where all the PCs are ranger-gestalts with other classes) I required that no character have more than one companion total from their class features (animal companion/familiar/paladin mount/etc), and aren't required to have any. Some of my players took a animal companion in the form of a warhorse mount, and others took a feat with no animal companion. It's worked out.