Crimson Trace makes the best grip for the Sig P220.
Shooter's Resource has the best price available on them, for $241:
It is a great rubber mold over polymer design that gives one a very secure, tight grip, that is also very comfortable to shoot with. Nice finger grooves on the front too. And, of course, the awesome Crimson Trace laser.
My P220 also has a fantastic standard length stainless match barrel in it, made by BarSto:
It really looks great with either a stainless or nickel finish slide.