Dawn and I saw The Spiderwick Chronicles this weekend and I must say I loved it. Its got that Harry Potteresque fantasy thing going for it but with more present day characters and settings. The basic concept is that every imaginary being (ogres, goblins, hobgoblins, fairies, pixies, etc..) are real and of course there's always the good vs. evil thing. The special effects are great and while this will clearly be an series you get the sense there is a lot more story to tell and a lot more amazing creatures to meet.
Its based on a series of book which I have never read. The Harry Potter films never made me want to read the books, but based on the movie, these look like 'young adult' books I might actually enjoy.
Definitely worth seeing. My only warning would be to avoid matinees as you will be swamped with kids. We went to an 8 o'clock show in Ballard and even then there were a lot of kids, some younger (and louder) than should be out that late (go on a school night).