I've got several but find from start to finish I only normaly use three hammers, for welding up a billet and rough forging I use a 8lb. sledge I modified by choping the handle, I use a a 2.5lb. shop hammer(mini sledge type head) for closer foring to shape and a 1.5lb. cross pien for finishing the bevels and doing any tweeking. That's when my power hammer isn't working, if it's working I do everything but the welding with the 2.5 and 1.5 pounders.
Every hammer I've got I've dressed and polished the faces on, getting rid of any sharp edges.
I don't use the vise to straighten a blade, I bump it a little one way then anouther till it's flat, on the upward curve that I sometimes get too much of I use a chunk of wood as a mallet and knock the curve out of it a little. The wood doesn't mess up the metal as bad as hitting it with a hammer.