If you want to get a nice hammer that is well made and completely hand forged, check out these http://www.oldworldanvils.com/hammers/index.html
I think I just saw one of his rounding hammers on eBay this morning. You might want to check it out.
I agree with longstep, for the most part they're all good. There's not a lot more you can do with the
traditional cross pein. That pattern has been around for at least 200 years, hanging in the hands of
men who depended on it to make their living and support their families.
That said, I like Peddinghaus hammers, but I'm careful to not use them for striking chisels and punches
because the faces are a bit softer (not a bad thing here). I've bought all but one of my hammers used.
With used ones, you can usually see whether they have defects in construction. Several of mine are
blacksmith made.
Dependable brands I can think of of the top of my head are:
Heller
Atha, Atha/Stanley, and Stanley
Champion
Stiletto (always good material and great balance)
Warwood has been in business since 1857, and while you don't hear much about this maker, Warwood
has been supplying the government and railroads almost from the beginning. A brand new cross pein
two pounder runs $25. Almost nobody thinks of Warwood, so it doesn't command "collectable" prices.
If you find a Jay Sharp, just buy it. Especially if you find one for under $200.
Channel lock made some, and I'm fond of my example.
Super Duty is essentially a Heller. Very good hammers.