Generally, over here in the UK, people are "into" the same things that the americans and canadians like. The fashion is very similar and people over-here aspire to look as good as your "A-list celebs" like Nicole Richie, Micha Barton, and our Bristish Magazines are full of pictures of them. As far as music goes, people listen to alot of American bands/artists, popular ones at the moment are the mainly commercial ones such as My Chemical Romance. Hellogoodbye, Rhianna, Fall Out Boy, Hip-hop artists, RnB artists etc are also popular. As far as other music goes which is British, the indie scene is becoming more and more popular, bands such as the hoosiers and kasabian are popular, or lily allen. Also popular is techno-rave music, which is also having an effect on peoples style. Ultra-violet clothes are really popular, especially long t's and very colourful skinnyjeans with pumps or nike trainers.
As far as customs go, britain is becoming more and more americanised. The obsession with tea is now turning to coffee with the help of Starbucks. The good old doyle (a thin piece of paper which is really very decorative which is put under cakes on plates) is dying out, and more and more american TV shows dominate the english channels. The bristish still have though, the obsession with the weather, especially now with the flooding that has taken place lately here, mainly in england. But, other hot topics of conversation are bush, blair and now brown.
Britains are also fairly into comedy, shows such as Mock the week, never mind the buzzcocks and have i got news for you? are firm favourites. As well as the comedians "French and Saunders". (look up the shows and French and saunders on youtube... brilliant clips there).
Hope that helps!