For the past three years, my streamer rod (real streamers that is) has been an 8wt Orvis Zero Gravity. IT handles all the lines that I might be fishing whether we're talking floating big bass bugs, or deep 350 sinking lines for trout and other critters.
Plus, with it's light weight....it's much more comparable to throwing a 5 or 6 wt all day as opposed to the 8wt.