Although I think KG will have a big bounce back season, being fully recovered from his knee surgery, and having the benefit of playing with Shaq and Jermaine, my vote goes to Ray Allen. The man was on fire until Artest took out his leg, and with a new contract and renewed focus on our post game, he will flourish. He plays much better when his future is not up in the air, and he will get a ton of looks when our post players like Shaq and KG kick it out to him, and he will also benefit from some more improvement from Rondo. Look out for Ray next season!
I also think Rondo will be even better, I think it will come from improved free throw shooting leading to more confidence in him taking it to the hoop. I think Pierce will be Pierce, he not going to get any better or worse, he will just take it easy a little more often. Quisy can't do much worse than last year, but I still don't expect a great deal from him, I think Wafer will be our primary wing backup. Perk is a wash, as he may not even play. Baby and Nate will have their ups and downs, IMO.