Mistborn: The Final Empire by Brandon Sanderson

This book seems to have a little of everything: a great system of magic (here, Allomancy), which is well thought out and has real limitations, a story about trust and coming of age on the part of the heroine, just enough mystery to make it interesting, and a fascinating world of oppression, set up after the Lord Ruler (a slice of the infinite God) defeated the Deepness (the real nature of which is entirely unclear at this point). I loved the developing relationship between Vallette/Vin and Elend Venture, I loved Kelsier and his plan, and I can't wait to read the next two in this series. Best fantasy I've read in a long time.