Actually, rabbits don't "purr". What they're doing is grinding their teeth when they're happy, so it sounds a little like cat purring, but it's not. They don't have vocal chords, so they don't vocalize like most mammals we're used to.
Rabbits make great pets, but as mentioned above, you WILL need to bunny-proof. They'll chew on anything they can get their little teeth around. So you'll need to cover up/remove things they shouldn't chew on, and give them toys and hay, so they have something appropriate to chew.
My Flash likes chewing on cardboard boxes, willow baskets, and even whitewood 2x4s. When I moved into my current apartment, I had to put plastic edges on the corners of the walls and baseboards, to keep him from chewing on them. And he's not allowed in my bedroom, where there's too much trouble he can get into.
Also, someone mentioned bonded pairs of bunnies above, so I thought I'd throw out a HUGE warning for someone who's new to bunnies. They're very territorial, and always establish a "pecking order" when they socialize with each other. That means you can't just grab two bunnies and make them live together, because they WILL fight for supremacy when they first meet, possibly with bloody results. Bonding a pair of bunnies is a process that takes time and patience.
If you want two of them to keep each other company while you're not home, your best bet is to ask the shelter you're adopting from if they have an already bonded pair that you can adopt together. Most shelters with lots of bunnies will have some pairs like that. Also remember that bonded pairs might not be as affectionate as solo buns with their human families, because they have each other for companionship.
As mentioned above, the House Rabbit Society web site, rabbit.org, is THE place for bunny info, so definitely go there and read up on diet, toys, litter training, bunny proofing your home, etc before adopting your first bun.