For me, going out for a meal = going out for a curry, pretty much, I'm afraid. And along those lines, I'd reccommend, above most others, Jaflong on Crookes. Butler's Balti House ( by the university roundabout) used to be excellent, but I haven't been there for a few years so I can no longer vouch for it. Though that new one opposite Netto's in Walkley is fairly nice, and Indian Chef is sometimes good but a bit inconsistent, Jaflong still remains unbeaten in that part of the world as far as I'm concerned. If you were looking for a school dining hall feel, Kashmir Curry Centre is still up to its old high standards, so I'm told. Though I imagine that you're not.
I know a couple of Italian restaurants - La Civetta in Hillsborough (no use to you, I suppose) is very nice, though it's got a lot more expensive over the last few years, and Maria's on Crookes is thoroughly pleasant also.
I'll let you know if I remember anywhere else.