Oh, I love Lone Wolf series. It is one great gamebook after another and non of them can be called bad, in my opinion. I even replay them on projectaon from time to time.

Figthing Fantasy are the first gamebooks I played but there are not so good and I dislike that in most of them you have to follow one single way adn do exactly the right things to beat them and often these things are really counter-intuitive. And some of them are unbalanced and devilishly hard. They claim you can win with any stats but this is just lie.

Like in Deathtrap Dungeon. There is so many fights you have to fight if you want to succeed that it is ridiculous (Gargoyle of whatever it is (9 CS but you fight with -3 penalty), Minotaurus (10), Barbarian (10), Ninja (11), Mantichore (10), Ceratosaurus (?)(12), the Pond Monster (?)(12 but you can win it after one hit) and these are only from top of my head). Low Fear score in the House of Hell also makes it virtually unwinnable.

From those I played the Caverns of the Snow Witch is worst one as it is terribly absurd and doesn't make sense most of the time. I disliked the Freeway Fighter strongly as well. Another case is the Creature of Havoc which, in czech translation, had terribly (and incorrectly) explained the way how to decipher the language and I threw it away unsuccessfully after getting stuck very early. I returned to it few years later only to find it is quite easy cipher and I was finally able to enjoy it, although it has the single correct path issue too.
One of the best Fighting Fantasy books is the Sorcery series as it doesn't have only one right path most of the time.
Not many others were released here. Grailquest was but I never tried it.
I played few others from other series too but it was usualy only single gamebook. As the one where you play some medieval french guy who travels to another world and you can even fight enemies with psychic strength.
There is also nice czech series, Negart Group gamebooks. It is set into one world, sometimes you play the same character, sometimes you meet character you played before, which is cool. You can even become werewolf or undead in some of them. It is quite good but some books are great (like the one where you play as necromancer commanding skeletal and orcish armies, sacrificing prisoners, casting spells and conquering cities), some are good or OK and some are just bad (One where you gain XP but it is unbalanced and in the last third of the game you don't have to even roll a dice in fights because you are just too powerful; or the one which is badly unbalanced and you have virtually no chance of winning if you don't cheat as almost every enemy is stronger than you.)
Yes, in the Sorcery! you can play either as fighter or mage. It is part of Fighting Fantasy but hte only ones that are direct continuations.

You are not alone. My first Sorcery! book is splitted to about 15 parts. :-) Another one that suffers from this is the Freeway Fighter which can't be finished anymore as I miss several pages.

I even had a game book set in the world of Asterix the Gaul once. :D
The series was called Alea jacta est!

Heh, same here and it still is one of my most treasured books. I played gamebooks long before knowing that "real" roleplaying games (like Ad&D or Call of Cthulhu) even existed, but i think it prepared me to it! :)
Wow, never heard about those Asterix gamebooks, and I'm french!! Shame on me! :D

Still have a complete set of Fighting Fantasy books upstairs.

Need to sell them to someone who would appreciate them a lot more than me.

It would depend on the price you would ask for it (and shipping issues, of course), but I could be interested. I never had any Gamebook in english, since my native language is french, so that might be entertaining!