Manchester Airport is a major international airport here in the UK and as such has the full range of shops and food places. Nothing spectacular in the food stakes- there used to be a kind of sushi bar there which was quite cool but I'm not sure it was still there last time I looked. Just all the bog standard things, nothing too hideous, nothing too great. I do like their O'Brien's Irish Sandwich Bar because it has nice comfy sofas in it, but you have to be quick, because it's small.
I did sleep there once as previously mentioned which was OK.
Warning: there is indeed a train station there, but it is a bloody long walk from the terminals so don't be thinking it's a quick change and there's no coach service between or anything so you have to walk it.