Guess I could have put this under Gear Deals...
My preferred DSLR case is the Think Tank DH-20. I hang it in front of me from my shoulder straps for instant access. It's not ultralight but it's tiny compared to a Lowepro. The slightly smaller DH-10 (for a small DSLR with kit zoom) is half price this weekend at Naturescapes: http://www.naturescapes.net/store/think-tank_photo-digital-holster-shoulder-bag-10.html