A fighter is defined by their choice of weapon and fighting style. This guide will help you make these choices to create your ideal fighter.
Ability Score Optimization Edit
Constitution - - Adds HP and healing surges, which are always good to have. Axes require some Constitution investment. Hammers require absolute dedication to it. The only flaw this stat has is that it boosts the same defense as Strength, and Battleragers don't even care about that. (Recommended Starting Score: 13-16, before racial adjustments)
Dexterity - - Gives you Reflex defense and AC in light armor. The thing is, Fighters can use shields (which boost AC and Reflex) and/or wear heavy armor, reducing their need for it pretty drastically. Flails, Heavy Blades, Light Blades, and Spears require investment in Dexterity to varying degrees, with Heavy Blades requiring a smidgen and Light Blades requiring a ton. Two-handed Fighters might want a decent score here, since they don't use shields and therefore their Reflex defense is lower. Its saving grace is that it does boost initiative, which is important for all characters, and that Scale Armor (your best armor on default) requires a decent score for specialization in it. (Recommended Starting Score: 12-14, before racial adjustments)
Intelligence - - Your designated dump stat. Has a redundant function with Dex (except initiative), grants you a bonus to skills you will (hopefully) never have to use, and aids no weapon group. The only use for it is MC; otherwise, avoid it like the plague. (Recommended Starting Score: 8-10, before racial adjustments)
Wisdom - - Makes you stickier, and boosts that all-important Will defense (the bane of Fighters since, well, forever). Polearms demand a decent score here, and some Paragon Paths (like Pit Fighter) make you a slave to it. Tempest Fighters are some of the ones who like this stat nice and high. (Recommended Starting Score: 12-14, before racial adjustments)
Charisma - - Useless for fighting, and boosts the same defense as Wisdom, BUT it does see some use in your skills (Intimidate being the shining example). Tieflings actually want a decent score here, thanks to all the shenanigans they can pull off with Infernal Wrath. (Recommended Starting Score: 8-12, before racial adjustments)
Fighting Style Edit
This is one of the toughest choices in a Fighter's career: the choice of style is irrevocable and influences many things about your character. Evaluate, and choose wisely.
The Battleragers are real tough and durable guys, especially in Melee, thanks to a steady stream of temporary HP. To boot, you get a little more damage from having the temporary HP if you're willing to let your AC drop a bit. The problem with this approach is that if you don't go for the damage and suit up in scale or plate, you will present a less tempting target, since you're less accurate and damaging than a standard Fighter.
The Tempest Technique hands you quite a few bonuses for going with off-hand weapon, making you the most damaging Fighter build out there, about on par with Strikers if you trick yourself out right. Just don't expect to hold the line for too long if you do, though; you will invariably have to sacrifice some durability, which means you're a blur between Defender and Striker.
The Weapon Talent is pretty versatile, with the ability to go sword-and-shield, two-handed, or two-weapon fighting, especially if you multiclass. Your power may seem to be underwhelming, and you would probably like to have some of the fancier special abilities, but that's the price to pay for a solid class feature with almost universal applicability.
Battlerager Vigor Pros: Potentially heavier damage, increased Melee durability Cons: Weaker attack bonus, restricted weapon choices, less stickiness/weaker armor choices
Tempest Technique Pros: Striker-level damage Cons: Low HP, mediocre armor selection, restriction to off-hand weapons
Weapon Talent Pros: Higher attack bonus, versatile Cons: Lack of special abilities
Weapon Group Edit
Axes - - The members of this weapon group deal a load of damage, though not quite as much as Hammers. They only require a mediocre Con investment, which frees up your stat points to travel elsewhere. To boot, they're available in all the flavors imaginable for a Fighter: one-handed, two-handed, two-handed reach, and off-hand ranged. However, a crit with one of these babies can REALLY ruin someone's day. Also, their superior versions (Waraxe and Execution Axe, Adventurer's Vault) do some obscene amounts of damage.
Flails - - Deals a load of damage, and though the support is a bit weak, it has some very nice perks (like Rain of Blows). The Dex investment provides some well-roundedness. The triple-headed flail (Adventurer's Vault) is a good choice here.
Hammers - - Deals a load of damage, even a little on a miss, and give you more toughness due to their ravenous hunger for more Con. Requires unwavering devotion to Con as a secondary stat. The Craghammer and Mordenkrad are excellent choices from the Adventurer's Vault.
Heavy Blades - - Their (usually) high proficiency bonus means a better hit rate, which means more stickiness on OA's. Additionally, Heavy Blade Opportunity means you get to have some fun with the people who try to get past you (and fail in a spectacular fashion). Also, their Dex focus means your defenses will benefit from focusing on them.
Light Blades - - Under par for most, especially because many powers for them can be used by Spears or Heavy Blades, and they work better for you. If you do use this, for the love of the gods, PLEASE pick up a Rapier (or a Two-Bladed Sword from the Vault) so you can deal some good damage. Requires heavy Dex investment, though.
A notable exception to this rule are the Tempest Fighters; they exult in Light Blades, especially the Two-Bladed Sword.
Polearms - - Reach is good; not quite as powerful as in 3E, but still nothing to ignore. A Polearm Fighter works best as a second-rank Defender, however. A good note is that its focus on Wisdom ameliorates the Achilles' heel of Fighters across 3E and 4E: Will. So far, all of them share another weapon type, so you can have some more fun with them.
Spears - - One word: control. A one-handed Spear Fighter can really control the battlefield with this thing. You pay for it with a low damage for your proficiency bonus, though. The Greatspear from the Adventurer's Vault, however, has good damage, a high prof. bonus, AND Reach, which is tasty. Also, the Tratnyr has Javelin throwing range on Spear stats. Nice.
Staffs - - Bad damage, two-handed only, and no perks whatsoever for you. If you MC Wizard, you might consider this, so you don't have to switch weapons, even despite the fact that it's the worst weapon group right now (heck, not even Fighter weapon group Encounter powers support it).