The Bull and Gate in Kentish Town stopped doing music I think, but not The Forum as far as I can tell.
My favourite venues:
Camden Underworld - very good for intimacy and getting close to a band, seen some great gigs there
Star and Garter, Manchester - again, small and intimate and I like the way it's positioned right above the pub. Good location for the train station too.
100 Club, London - Not that spectacular a venue but I loved it for the history [during the punk era it was legendary] and it was a privilege to see Witchsorrow play there.
Yorkshire House, Lancaster - used to hang out here a lot at uni and saw some good gigs in the upstairs room.
Astoria, London [RIP] - My favourite London venue, but sadly Crossrail brought things to a close. Saw some great gigs there and it felt spacious but intimate at the same time, if that makes sense. Hawkwind's show there in Xmas 2003 remains in my top two or three gigs of all time.
Brixton Academy - Dirtier and scuzzier than Hammersmith, and I prefer it slightly for that reason - more grit to the place. Last time I saw Motorhead there was one of the loudest shows I've ever been to.
Ritz, Manchester - Unusual venue to see a band in, sprung dancefloor and more of a ballroom than a rock show place.
Brighton Centre - not because it's that unique, but because it's right by the seaside, and it feels slightly strange going to the beach to see a rock concert. Plus the Heaven and Hell show I saw there was absolutely amazing.
The O2 - What they should have done with the Millenium Dome in the first place they eventually did in 2007 and tbh even though it's a big corporate arena it's how a big corporate arena should be - comfortable seats, good viewpoints/acoustics, easy to get to, a lot of nice eateries and bars to dine at and it seems to have more character than a lot of larger venues.
Emirates Stadium [Arsenal's ground] - Went to see Muse there last Sunday and was very impressed by it, good modern building, quite a bit of character and easy to get in and out of - stewarded well too. Not quite so good for how long it takes to get back to the tube station after a show though - lots of queuing required.
[Edited by sabbathfan at 09:05 on 28/05/13]