it all depends what kinda choc you like.
if youre into milkchoc thats really smooth lotsa milk lil cacoa then cadbury milka etc is fine cause they use a blend of beans so the smooth taste is always there. Its choc you grab on your way out to work or so, theres a reason why cadbury has all these machines in the London sub.
if youre a choclover and like 99% pure or exotic tastes then there are many - small - brands that are a lot better, they use beans from Venezuela, google it and youll see why I know and many dutchies: we produce a shitload of choclate.
Plus Im close to belgium, so all the gourmet chocs are right around my corner. If you wanna look at some gourmet stuff:
http://www.neuhaus.be
http://www.leonidas.com
http://www.godiva.com
this is prolly the top 3 best known and can be bought all over the world
Oh and lindt is bad at all - its wellknown cause they sell it on every airport, its swiss and pretty good as well, its more pure choc as in no filling :
http://www.lindt.com