Our domestic rabbits' wild ancestor, the European wild rabbit, is the only rabbit species that has been observed to live in groups. Every other type of rabbit is solitary. As Chickerdoodle said, the wild colonies don't exhibit what is thought to be typical cooperative community behavior; one theory holds that the rabbits are living together because they are forced to by a lack of other suitable sites in their human-altered and limited habitat. There are no "friends" in a wild rabbit colony, only rivals to be dominated or avoided, so it sounds strange when someone talks about getting a friend for their pet rabbit. In the wild, each burrow within the warren has one owner - the rabbit that dug it - and every other rabbit that enters it is savagely attacked. How do you rectify this with the stories of "bonded" rabbits that pined away after the death of their cage-mate? Can this really be the same species?
My theory is that we are altering the very nature of the domestic rabbit. Just as with dogs, the normal behavior of the adult is not as appealing as that of the youngster, so we are deliberately selecting for animals that continue to display "young" behaviors into adulthood. Baby bunnies are programmed to snuggle together; if they don't, they die of hypothermia. Nobody likes getting attacked by their own rabbit when they put their hands in its cage, however normal such territorial behavior may be in an adult. We want our rabbits to be friendly with us; as we breed for this, we may be making them friendlier to their own kind, as well (though that isn't always the case; I had a buck that adored my attention, but was really nasty and aggressive with the does he bred).
So when the debate "are rabbits social or solitary?" surfaces, my inclination is to say, "both." Some rabbits seem to prefer company, but anyone who has had enough rabbits can tell you about the rabbit that simply doesn't tolerate another rabbit, no way, no how. You can't be sure how any rabbit will react to another rabbit, or how any two rabbits will get along. Given a large enough space, most rabbits can learn to tolerate each other, but whether two rabbits will truly become friends is hard to say. So IMO, whether you get another rabbit is entirely up to you, but if you play with your bunny and give her a stimulating environment, you shouldn't feel that you are "depriving" her by not having another rabbit. Getting another rabbit could be a marriage made in Heaven, or not - and there is absolutely no way to be sure, ahead of time.