If you are already signed up to Songkick, it's really convenient to buy tickets through the site as they will email to let you know when your favourite bands are playing and include links to the ticket shop. I've found that they sometimes have tickets that are sold out elsewhere too, which is great.
Best of all, the process feels transparent and honest, and I don't come away feeling completely ripped off as I do with other ticketing companies.
I just hope they don't change things!