As someone who actually sleeps, lives and breathes in Aberdeen at the moment I felt that it may be of some use to get my perspective (even though its my first post).
Aberdeen is a nice walkable city. Of course there are some dodgy areas as others have mentioned (Torry, though its going under a slow regeneration, Northfield, Sandilands etc) but all cities have that. There are many green areas throughout town, and the benefit of living this far north means that not only do we get a fantastic light quality all year round, but the residents all spill out and use the pars whenever there is the slightest hint of sun.
The beach is easy to reach to by walking. Its about 15 minutes out of town, or a 5 minute bus ride. There are fantastic clean sands for lounging around or surfing should the weather permit. Aslo the promenade is always full of people walking or cycling.
Aberdeen is quite an expensive place to live due to the oil based economy, so rent/sale prices are more stable than elsewhere. The west end is a great place to stay, but due to size of Aberdeen most decent places are relatively easy to get too thanks to the monopoly that First Transport have on communications. Try ASPC (search online) for the main leasing agency.
As for pubs and restaurants there are too many to mention all of them, but here are my personal favourites:
Under the Hammer - local feel pub with brilliant ales
The Grill - completley authentic whisky bar
Cafe 52 - best food in town (contemporary Scottish)
Cinnammon - amazing Indian which wins numerous awards
Yaitai - the best Japanese restaurant I have experienced
Hope that give you a brief insight. If you have any specific questions then I am more than happy to help.
Bill.