I've lived mostly in condos or apt.s after graduation, and, yes, there were a couple where neighbors/thin walls were a nuisance. But, for the most part, as a single, I didn't enjoy living in a house - it feels too big. HOA's could be bothersome, but, it's not like one has to deal with them frequently. In return, there's the advantage (as a single person) of security, no maintenance to worry about, the pleasures of city living, etc.
In terms of size, <1000 sq ft is difficult, although, it really comes down to what one's basic necessities are. I need a good amount of space for stereo, movie viewing (not necessarily home theater) and a 2nd BR/BA for visiting friends. That said, I've lived in 1 BR/BA places with ~900 sq ft without a problem. Visitors had to deal with the pull down sofa, but, way back then I didn't care and if the visitors did, it was their problem.
For furnishing a small space, here's some space saving Italian furniture
ideas to consider.
All the best with your new condo!