By "starter creeker" do you mean you're a beginner and would like do do some easy (II-III+) creeks? Or that you're expecting to step up to Class V sometime soon. If you don't expect to be into the Class IV+ to V range any time soon, at your weight I would say the Mamba 8.1 is a great boat. You could run Class V with it, but I would probably recommend a slightly larger boat (maybe a Nomad 8.5/8.6, Large Burn, Medium Karma, etc.)
I have a Mamba 8.1 at 180 pounds, its great for creeks up to IV-, and awesome for big water, but when I've pushed it past that level I'm a bit too big for it and have wished I had a bigger boat. So I bought a Nomad 8.5 (kept the Mamba for easier stuff) and its definitely bigger and easier on harder creeks -- just what I was looking for to ride high on the water and not worry about endering or catching an edge in IV, IV+, V- stuff which is where I'm hoping to step up to.
If you're just taking what you can get used, then just make sure you get a recent model creeker where you are in the bottom half of the manufacturer's weight range. If you don't like it you can always sell it for about what you bought it for and buy something else. If you've got a "new" budget, then go do some demos! I'd say try the mamba M and L, karma M, zen M, new nomad M, burn L, shiva M, 9er, and zet Toro and liquid logic Flying Squirrel 85 if you can find them -- that's pretty much the US market for creekers right now. Not sure if there is any reliable distribution for Waka Tunas but they look sweet.
Kevin K. in Boulder is selling a nearly-new Nomad 8.5 (i think I saw it on CL) for a fair price.