Following around past the Corn Exchange, we get to Regent Street and St. Andrews Street (near Emmanuel). This is home to Cambridge's large pubs - the Rat & Parrot on Downing Street is worth avoiding. The Castle has had a turbulent time recently, changing hands just again whilst this is being written. Next door we have Cambridge's (and supposedly the country's) largest pub, the Regal. This is a Lloyd's No. 1 chain pub, and as such has a reasonable range of very cheaply priced real ale. It does get very busy on a Friday or Saturday night though. A little further down the road (towards Downing College) we have the Fountain. This has been quite recently refurbished, and will normally have at least one beer from one of the local breweries.
Cutting across Parker's Piece from the Fountain, we get to another small group of pubs. The Elm Tree (Orchard Street), Clarendon Arms (Clarendon Street) and Cricketers (Melbourne Place) are all good pubs. The Free Press (Prospect Row) is arguably the best pub in the area for real ale, with three or four different beers all in good condition, including the somewhat rare Greene King Mild. It's non-smoking throughout, and has a strict no mobile phone policy. Around the corner from the Free Press is the Tram Depot (Dover Street), a large Everards pub with a good range of real ale.
Just north from these pubs, we get to King Street. This short street has 5 pubs and is the route for the King Street Run pub crawl, involving a pint in every pub. This was an even more serious proposition in the past when the street had 8 pubs. The St. Radegund is very near the end of the street, and is probably Cambridge's smallest pub. It normally has 1 or 2 beers from the local Milton Brewery alongside 1 or 2 other real ales, and is well worth a visit. The other pubs on King Street all have their merits, particularly the Champion of the Thames.
Bridge Street (between St. John's and Magdalene College) has three pubs, all selling real ale. The Baron of Beef and the Mitre are right next door to each other, both with a choice of ales. Just over the river sits the Pickerel, which normally has 5 different ales, most of which aren't often seen in Cambridge city centre pubs - Theakston Old Peculier is a regular beer here.
Heading up the hill away from the centre, we get to the Castle and the County Arms. Both have a good range of real ales. The Castle stands out in particular - it's an Adnams pub but always has some guest beers on, always in good condition.
A bit further out we have the Carlton Arms, on Carlton Way. This is a non-smoking pub with an excellent range of real ales, and it has regular beer festivals.
The bulk of Cambridge's best pubs lie to the South East of the centre, off Mill Road. The Live & Let Live (Cambridgeshire CAMRA Pub of the Year for 2006) on Mawson Road is truly wonderful, always having a range of real ales covering many beer styles. Like the Carlton, the Live has regular beer festivals as well. On the other side of Mill Road we find the Cambridge Blue (Gwydir Street) and the Kingston Arms (Kingston Street). The Blue is another non-smoking (and no mobile phone) pub, and has been for many years. It has a large range of ales in good condition, and is notable for its rowing memorabilia. Likewise, the Kingston has a wide range of real ales, all in good condition.
The villages around Cambridge have a number of notable pubs. Just to the North, the Red Lion in Histon and the Waggon & Horses in Milton are both excellent. Further to the South, the Queen's Head in Newton is a true gem - it's appeared in every edition of the CAMRA Good Beer Guide, and with good reason. Beer range is not massive there, but beer quality and welcome are top notch.