I forgot about HIccup, they're fab as well. I think that Windsinger might be a little bit old for a 10 year old, my boys were a little older, but it depends on the child. I really liked them, also Phillip Pullman (but not Sally Lockhart books.) Some of Robin Jarvis's books might be suitable, also The Scent of Magic by Cliff Mcnish.
DS2 LOVED Edge Chronicles, also Broken Sky.
Septimus Heap is good as is the Seven Fabulous Wonders series. The Bartimaeus trilogy by Johnathon Stroud was very popular in here, as well. If he likes Arthurian stuff, you can't beat Kevin Crossley-Holland. Also the Warriors of Alavna/Camlann. If he likes a scare, the Deptford Mice books are cool. Roman Mysteries are really good as are Rosemary Sutcliffe's books. I also like the Children of the Lamp series. My favourite, apart from Artemis, though is Garth Nix. ALl his books are brilliant, but maybe just a little to old for a 10 year old. I loved his Abhorsen trilogy, but in retrospect, I would maybe wait a year or two. I also like the Diamond Brothers books by Anthony Horowitz. They are hilarious.
Artemis is a whole series of 6 books, at the moment. The next one is out nest month. You have to read them in order, but that isn't a hardship. I will keep thinking. I think that we have read almost every fantasy/history/myth type book ever written for this age group.