ok I'm better now...
parts of Withington can be nice- you have to investigate. Didsbury, Chorlton, Cheadle, parts of Northenden.
Pretty much anything in or near the city centre is bad. There are some very very trendy (translation: expensive) city centre developments but they're right in the city centre. I'm not a big fan but then again I have a child. City centre is busy, loads of students, drunks during the weekend. If you're young and into going out a lot (dinner/clubbing/drinking) you'll probably love it there. I'm old and crotchety so it doesn't appeal to me.
Fallowfield and Rusholme are filled w/ students or recent grads that haven't moved yet. It's not bad in that it's dangerous but just very studenty. Rusholme is where curry mile is and has loads of Asian businesses- great curry houses and some yummy looking pastry shops. All the places Andee mentioned as bad are TO BE AVOIDED they're dangerous (shooting, gangs, drugs). I'm sure it's not all bad but if you're not from there... I would add Victoria Park, Longsight, Blackley and basically anything in Wythenshawe.
I don't know anything at all about N Manchester- I live w/ a s manchester snob!! His opinion is that it's very grey/industrial. I'm sure there are lovely places there I just don't know.
Manchester can be expensive. The nice areas outside of Manchester are expensive. I'm sure Londoners will laugh but you have to factor in wages. You're young and don't have kids so that will work to your benefit as you'll not be looking at good catchment areas and that usually drives up the prices.
Also nice is Altrincham, Sale, Salford, Timperley.
If you get the job just ask someone here and we'll tell you which places to avoid. Some are seriously dangerous and some are just not to my liking but very livable. OK I think I'm done now and I'm sorry if I sound like a huuuuge snob.