Haven't read her books for a while but I love Trudi Canavan's Black Magician Trilogy. The sequel trilogy A Traitor Spy is okay too, it pretty much carries on from the characters from the Black Magician when they're older. And not forgetting the Magician's Apprentice which is a stand alone prequel to the whole series. Doesn't matter if you read the prequel before or after the Black Magician trilogy as it doesn't spoil anything but there's some things that make you go "Oooooh that's how that happened" in it.

Personally I'd suggest reading the Black Magician trilogy (The Magicianss guild, The Novice, The High Lord) first, then read the prequel simply for those 'Oooh' moments. (The Novice, is my personal favourite simply because I love one of the recurring characters that when you read it you'll know immediately who it is. No... seriously you will.)

Trudi Canavan's Ages of five trilogy are okay. I need to read those but I'm much in love with the Black Magician books.

I currently have the first book in her new trilogy called Thief's Magic. I haven't read more then the first chapter yet but there's a bit of a steampunk kinda vibe to it with magic thrown in.

My other favourite author is Marcus Sedgewick. He normally just writes stand alone novels. A dark flight down, and another one I can't remember are the only ones that I think are tied together. My personal favourites of his though are Floodland(s) and Revolver.

Lastly there's Carrie Vaughn's Kitty Norville series about a werewolf radio host. 10 books in and it's just awesome.

I'm really enjoying the chronicles of kazam series by jasper fforde. It's a funny take on the classic fantasy book. the first book in the series is called The Last Dragonslayer :)