Like NUFC1 says, it depends on what you're after. There's over 100 pubs in walking distance of the ground and if you're staying semi regular there are plenty of opportunities to find the right one for you.While you're here, you don't feel like recommending a pub in the centre of Newcastle for a pint of decent beer do you?
I'm up here semi regularly but always seem to find myself in the pub opposite the station or Wetherspoon-type places.
Bridge Tavern is good for food and the terrace etc. The Forth is a personal favourite, decent selection of beers, good crowd, really close to the ground. Get out to the Ouseburn area and you'll find some good bars/pubs, Tyne Bar chief among them (great view of the quayside and bridges up the Tyne). The Wylam Brewery in Exhibition park is a big taproom in a Grade II listed building constructed to exhibit art back in the 1920s.
Tilleys is a bit less refined than the Forth, but it's got the sport on, and a good selection of beers too.