If you have a chance you should check out the Kensai prestige class in the complete warrior. at 9th level you could be paladin5/kensai4 human. A player in a game in involved in made this character with a large warhammer. He chose power attack and divine might as some of his feats during character progression. At 2nd level kensai the player can invoke his power surge ability with a DC 15 concentration check to gain a +8 str bonus. So as a 9th level character paladin 5/ kensai4 With your character having a 18 str (start at 17 add one for level 4), kensai granted signature weapon (+4 large warhammer 2d6 damage), taking a -5 for power attack, divine might bonus to from charisma (15 to start 16 at level 8), weapon focus you would have for one round a single attack at a bonus of +12 (+8 base attack, +1 weapon focus, +8 str, -5 power attack) with a damage of 2d6+25 (2d6 weapon damage +12 two handed str, +10 two handed power attack, +3 divine might bonus)
This build leaves room for one more feat such as improved init or improved critical. Few creatures can survive many blows which average 32 points or so for more than two or three rounds. If played right flanking bonuses and such can make the attack bonus go through the roof. Also a note to you. The weapon costs nothing save the cost of the masterwork weapon and experiance invested. The same thing can be done with a greatsword but we have an anti-undead campaign so he chose the hammer to maximize damage vrs undead.
