My son and I recently finished reading RICK RIORDAN's PERCY JACKSON AND THE OLYMPIANS series. The fifth and final book was THE LAST OLYMPIAN, in which Percy Jackson has his final showdown with Kronos, the super-villain introduced in the first book.
This book was an enjoyable read on its own and very satisfying conclusion to the series. Some of the events were predictable, but there were also a number of surprises. The characters evolve, the story has lots of action in it, and the plot is pleasantly free of cheats or contrived moments.
I would highly recommend this as a series to interest young people in reading. I have mentioned before that it borrows a lot from the J. K. ROWLING formula, but it definitely doesn't read like a cheap knock-off. Riordan infuses the stories with a style and theme all his own.