Chinchillas are social animals, so you really keep more than one or none at all. My daughter has had 3 chinchillas for about 7 years. The normal routine is that as soon as she turns out her bedroom light at bedtime, the chinchillas burst to life and are very noisy - bounding about their cage, running on the wheel, and occasionally making chinchilla vocalisations (although these are not in the same league as dog barking!). My daughter has always been able to sleep through it, although she is a VERY sound sleeper. Now that she is 14, and not quite as good a sleeper, she is starting to have a little more trouble. I wouldn't have lasted one night with them in my room, although I must admit that our cage setup and squeaky wheel is perhaps noisier than it could be.
They are a decent pet. Certainly interesting to watch and very cute. It is difficult, however, to train them to really warm to human company. Even with daily handling, ours are merely tolerant of us humans, although they never bite (at least not hard!). Personally I found our other rodent pets - guinea pigs and degus, to be more fun to interact with. As I'm sure you've been warned, their cages can get quite smelly if they are not cleaned out frequently - every 3 days or so for us. In my opinion, you would have to be a serious animal lover to sustain your interest in them for more than a few months. It's a big commitment, and they are long-lived little beasts!
Personal experience, and am a wildlife biologist.