I have managed to meet the British band Enter Shikari several times after gigs and at signings etc. Here is a picture of their new album Common Dreads (reached no.16 in the UK album chart, but I think number 2 in the itunes chart!) which I had signed by all 4 members at a signing in London in June.

I have met them other times and had different things signed but most just by 1 or 2 members at a time. If anyone is a fan of them and would like to meet them it isn't always necessary to go to a signing, the band are all very friendly and it is easy to meet them after a show as they usually come out to hang out with fans. They are my favourite band and are always so nice to fans

If you've not heard of them I'd reccommend checking them out, they're currently touring the USA but are back in England later this year.
www.entershikari.com