Very nice setup!
Get yourself a center weight next, it's one of the easiest and cheapest improvements - good to get early. For another easy and cheap improvement, I also recommend keeping an eye out for a bulk tape eraser, like
this one, at thrift stores and classified ads. I found one a couple of weeks ago for $15 and it's been tremendous. You demagnetize your records by waving it around over the LP for 20-30 seconds (away from your turntable or any other equipment), and it really adds life to the music. A plate demagnetizer also works really well and is a little more convenient, but is bulkier and more expensive. If you're going to be sticking with vinyl for a while, a center weight and a demag are going to become your every day tools, so it's good to get them early. A vacuum cleaning machine should be your top priority as far as more expensive purchases though.