Hmmm... favourites.... not really a fair question as different choc is required at different times.
There are the obvious ones; CDM, Whole Nut, Fruit & Nut, Bourneville as bars - each delicious in their own way and bring back Old Jamaica - I still buy handfuls of these whenever I find them in shops.
Of the rest, Picnic (not available everywhere), Star Bar, Double Decker, Wispa and Crunchie are regular visitors to my stash, not forgetting Flake (mainly with ice-cream unless you bring back the praline version, otherwise it is mainly Galaxy Ripple - sorry!). Buttons, don't forget buttons !!
Even the likes of Freddo, Chomp, Curly-Wurly and Fudge have their time and place. Time-out and Twirl appear less regularly.
Non-favourites are simpler; Brunch, Snack, Dream, Bliss and Boost (although the peanut variety was great!).
We should also take a moment to remember those who are no longer with us, especially Fuse and Old Jamaica (when this disappeared from our shelves for a few years back in the late 70s(?) when I was a kid, I kept my last two squares in the fridge for several years and would not allow anyone to touch or throw them away as you could still enjoy the smell !!
Anyway, I hear a Creme Egg calling me...