Extra needles for your machine. Nothing will peeve you off more than getting in a great groove, breaking a needle and not having back up.
Otherwise, everyone else said what I would say. :)
Welcome and enjoy the ride! Your first quilt WILL NOT be your last. :o)
Oh yeah, one more essential...THIS BOARD! I'm pretty new to quilting myself, but I have learned SO MUCH from this board. The wealth of knowledge is unbelievable. Use the search feature linked at the top of this screen, you can find an answer to almost any question!