Fighter Build - Baldur's Gate Dark Alliance
The Dwarven Fighter is one of the better classes in this game in my opinion since you're forced to melee some bosses (even if you're a ranged character). You have two choices are far as builds go when using this character, you can use a 2h weapon or a 1h weapon with a shield. I strongly recommend you use a 2h weapon because the benefits you get from a shield in this game are minimal.
Almost all of the 'active' skills that are available to the Fighter class aren't very good in my opinion. Bull Rush is ok but it requires too many points invested for it to deal good damage, Whirlwind Attack is decent too but it's an AoE only which means it'll be pointless against single targets. I would recommend you only get Whirlwind Attack - assuming that you are using a weapon that can activate this ability.
What I would recommend you do for this character is to focus on the passives, start with the most powerful ones like Improved Critical, Combat Reflexes and Death Blow. Once you've gotten these passives (the most important ones) you should start focusing on the lesser ones. Personally I would ignore the active abilities as a whole but if you have to experiment with one of them I recommend Whirlwind Attack.
Bull Rush requires a heavy Skill Point investment for it to be on par with your regular attacks as you level up and (in my opinion) that takes too many Skill Points away from other important things. I know this may sound boring to a lot of you because essentially all you will be doing is a regular attack the entire time while playing this character but... That's pretty typical for old school D&D - most Fighters used only a basic attack for many levels.
You'll find a list of all the skills I recommend purchasing on a Fighter below. They're not in any specific order and you should read the descriptions that I have for them to determine if they're the best choice for you.
Most important: Improved Critical, Combat Reflexes, Death Blow
Combat Reflexes: Each rank of this skill raises your Attack Speed by 15%, it's one of your best passives and you should max this out as early as possible.
Improved Critical: Improved Critical increases your crit chance by 5% per rank. This is the best passive available to you as a Fighter and you should make this as early as possible.
Death Blow: Death Blow increases the damage that your critical hits do. It's a flat damage increase and it's worth maxing out this passive.
Sword and Fist: Sword and Fist increases your damage by 1 point with each rank and it also increases your chance to hit. It's a nice passive and worth getting later in the game but there are other more important passives that you want to get first.
Intestinal Fortitude: Intestinal Fortitude increases your Health Regeneration with each rank. You should use this as a dump skill, once you've maxed out the important skills dump remaining points into this one.
Bull Rush: Bull Rush is a skill you can activate with the Circle button that uses Mana. I personally didn't like this one too much since it requires a heavy skill point investment for a rather small amount of damage.
Whirlwind Attack: Whirlwind Attack is a skill I normally get during Act 2 and use for the rest of the game. It works great when you're fighting 3+ enemies which happens quite a lot in games like this.