The Dresden Files by Jim Butcher. Starts with Storm Front
and book 12 Changes
just came out this month. If you saw the very very short lived tv series (12 eps) on Sci Fi in 2007 you got the gist but missed a LOT. Butcher usually puts the first couple of chapters on his website about a month before each is published:
I'm not really into his Codex Alera books but they ended in Nov after book 6.
I also LOVE Sherrilyn Kenyon's Dark Hunters and Patricia Briggs' Mercy Thompson and Alpha & Omega series. A&O is a sort of spin off of Mercy.