I lived in Rosebery 2 years ago and quite liked it. It's a good area near Angel adn Islington where there's a good few pubs and clubs and a comfortable 15-20 mins walk from LSE, social life was poor in my year but I think that was an anomaly, it was apparently very good last year (maybe it was just me ha ha). I think it offers the right mix between peace and quiet and a decent social life.
In response to whoever said Rosebery is overrated on TSR, I think that's because we were told on our first day by the Hall President that Rosebery IS the best hall and Roseberians have always been very loyal to it, so I think that subconsciously made us quite tribal about it from the beginning! But seriously though, its a good hall!