Just thought as a follow up, I'd add some of the great places which may not be common knowledge my wife and I have found in ChCh.
1) Rock Salt in Strowan. Lovely little bistro, superb food (calamari on bed of lime and chilli), great atmosphere, not usually too packed!
2) Canterbury Cheesemongers opposite art gallery in city. Sensation selection of cheeses. All your european ones, but best of all, some NZ rarities. All kept perfectly at the right temperature, and they do the best bread in NZ too!
3) Peter Timms butchers in St Albans (or small one in Bishopdale). The best fillet steaks I've had ever! Good value, great quality - and superb home made salami and sausages too.
4) Smash Palace on Victoria Street. Looks like an old tarpaulin over a bus (and effectively it is), but great craft beers, friendly people, and a unique atmosphere!
5) The Volsted in Riccarton - behind some shops. Small but quite brilliant bar, great craft beers, great friendly atmosphere. Going there tonight!