I would personally first buy a really nice ultralight down bag (western mountaineering or montbell), give in and buy a neo-air, and then spend the rest on some nice clothing (that is of course assuming you already have a light weight backpack, kitchen, etc.). You can easily live comfortably with cheap synthetic clothing from walmart or target, but the comfort and feeling of merino clothing and nice socks, jackets, etc. is well worth the price. Good clothing, to me, is what makes me feel most at home when on the trail.