and currently Kieron Gillen
^ I second the Kieron Gillen comment; the current God Butcher arc is absolutely bitchin'.
Gillen is not the current writer on Thor. Jason Aaron is.
Gillen is writing Iron Man.
Simonson's run is the gold standard.
I liked Dan Jurgens on the book as well.
Kieron Gillen wrote a great Kid Loki tale in the recently ended Journey into Mystery.