Rabbits can be great apartment pets if you know what you’re doing and spend the time and money to do it properly. Otherwise, they can be destructive, messy, smelly, even violent. If you want or have a rabbit, you must educate yourself about them and stay on top of the new information out there. There are books but there are also many excellent websites.
Most rabbits litter train easily. Even litter-trained rabbits, however, will poo outside the box. It’s a territorial thing. You can reduce this behaviour by fixing your rabbit and providing him with a space he sees as his own (i.e. encourage his sense of privacy and ownership over his room/pen/hutch).
Poo is not a big problem, really. Rabbit poo is hard small pellets that basically have no smell. Just sweep them up and throw them in the compost/garbage. Mushy poo or diarrhea is a serious health concern in rabbits, requiring immediate attention from a rabbit-savvy vet.
Rabbit urine does have a strong smell. You can reduce the smell somewhat by fixing the rabbit (reduces hormones in the urine). Also, some litter materials cut down on the odour more than others (but you should avoid cedar and pine – they can be deadly). No matter what, you should keep the box clean. (This can mean scooping every day, or complete replacements every two or three days. Either way, you should thoroughly scrub it out once or twice a year. White vinegar is amazing for breaking up urine deposits.)
Another thing about rabbits that causes mess is the hay. Your rabbit should be eating more hay than any other food group. Hay, of course, is impossible to contain and ends up all over the place. It has a nice smell though, and it’s easy to clean up with a broom.
Carpetting is fine for some bunnies, bad for others. Some rabbits like to dig in carpetting – bad for you. You can try to minimize this behaviour by providing your rabbit with suitable toys and activities so that it isn’t bored and destructive. More importantly, however, is that some rabbits like to eat carpetting: this will kill them. But, if your rabbit does neither of these things, it will be very grateful for carpetting becuase it’s more comfortable and easier to move around on, etc. Just keep a stain remover on-hand for urine accidents. (OrangeOxy works wonders.)