Depends on how well you know London? You could chose from a whole host of places from Blackfriars to Embankment. As for live music, I don't really know, but I'm sure there will be some. However, my favourite place to be, and not just on New Years Eve, is the South Bank. Although in the cold light of day it looks a grey concrete mess, there are in fact some nice pubs, bars, eateries, and cafe's around. The streets are full of performers, musicians, artists, lots and lots of Londoners and plenty of tourists. You also have a fairly good spot for any fireworks that should take place. Hope this helps?