I just spun up some Optim, which is incredibly soft and very easy to spin -- the fibers are pretty long. It's a little slippery for a beginner and wants to be spun very finely, but you might really like it.
Coopworth is a good beginner wool. I'd try something like blue-faced leicester next, or perhaps some 60's merino if you're feeling brave. But be prepared for a slight learning curve - both those fibers are shorter and smoother than coopworth! Another option might be an alpaca/wool blend, since you're interested in spinning alpaca. I bought some alpaca-finn 50-50 blend awhile back and it was both easy to spin and made fantastic yarn! It spun up quite fine, though... As I said, a learning curve is to be expected. Why not order something like one of Woodland Woolworks sampler packs and play a bit? That may give you a better idea of where you want to travel next.
I am in the process of spinning a hemp/Merino blend that I've enjoyed spinning. I'm really pleased with the way it is turning out. I don't know where it rates on the difficulty scale, but I'm not a great spinner, so it can't be too far up there.