Stay a fighter, or maybe 1 level of barbarian. With access to all of the books, there is truly a great feat choice at every step. Eventually you want endurance and iron will so that you can get Indomitable Soul and Steadfast Determination. I know you didn't ask for defensive feats, but in my opinion, these are just as important, and only the fighter can hope to have enough feats to spare on feat choices like this.
For offense, weapon focus, greater weapon focus, weapon spec./greater weapon spec., power critical, melee weapon mastery. Also, and this is important...from the PHB2, take the Overpowering Attack fighter class feature.
In fact, over 20 levels, you have enough feats to also enchant your hammer with the returning and throwing abilities and take ranged weapon mastery, brutal throw, power throw. Now, suddenly with the overpowering attack ability, you can as a full-round action, throw your hammer as if you were wielding it in melee AND do double damage automatically. Remember, you can throw with 2-hands and get 1.5 X strenth bonus.
Being able to throw your weapon and deal pretty much the same amount of damage every time (although only once/round) as you do in melee is very nice. I recently ended a campaign playing a dwarven fighter with the ax of the dwarvish lords, and it was pretty scary how much damage he could deal every round to creatures 100' away from him. The paladin became very jealous and much less anxious to charge into melee without me going in first.
Also, another fun feat is leap attack, but that's for melee. I think as a fighter you can take every feat that I've mentioned (I did), and more.
Remember, it's great than you can deal out 60 points of damage with each blow...but what happens when you blow your will save and suddenly find your target of choice to be your ally, the wizard standing behind you? Not good.
Ok, now I have a question...is goliath a template that can be added to, say, a stone giant? Or is it it's own race? I have a stone giant hulking hurler that I want to throw at my group, and I'm curious about the goliath as a template add-on, or even an alternative to the stone giant...sorry for the slight hijack.
