[quote=Skyrte]

Lastly, what determines a fight in space over all else? I read somewhere that Delta-V was the most important, but I want to hear your guys' opinions and thoughts on this.
[/quote]

Probably the guy who scores the first hit. 

In all honesty, the weapons that you'll be working with in space are going to be rather potent. Nuclear munitions (which will probably be fusion-based rather than fission-based), high-powered lasers, railguns and particle weapons all have potential for one-shot kill scenarios. Speed, distance and non-conventional defensive measures (measures that do not include tacking on heavy armor plating, since this will only increase your ship's mass) are your best bet.

I don't see generic sci-fi 'energy shields' coming into existence. Maybe plasma fields or powerful electromagnetic fields, but not the generic spacemagic fields found on the ships seen in Mass Effect or the Star Wars franchise. You might see a lot of different defensive tactics however, such as keeping a sizable difference between you and your enemy (which would, in turn, allow your vessel more time to evade incoming fire). If you're far away enough, you could evade light speed weaponry. 

Fighters are out as well, since a missile pretty much outclasses a fighter in every conceivable way possible. Not only are they lighter (which translates to more Delta-V conservation), but they're going to be cheaper than a fighter, tipped with a powerful thermonuclear warhead that'll probably be sitting in the multi-megaton range and be fired by the drove to minimize the enemy vessel's ability to evade them and shoot them down with point defense weapons. 

Bonus points if they come equipped with small integrated computers that enable the missile swarm to dynamically communicate with itself, allowing individual missiles to cut off the ship's route of escape, assault its flanks or distract the ship's point defense systems. There could even be dedicated missiles that act as mobile ECM jammers or 'dumby' missiles that fundamentally act as a distraction. 

Directed energy weapons, like particle beams and lasers, will be the highest echelon for firing range. Particle beams, however, will have reduced range when compared to lasers, but their potential for raw destruction and mayhem outstrips lasers in that particular field, since you can't defend against such a weapon using conventional armor (and just by how particle beams work in general; they instantly heat up materials that they strike and make them explode). Charged particle beams can be defeated by electromagnetic fields, but neutralized particle beams are not effected by such forces. 

Depending on the settings, a particle beam could act as an 'ion weapon', disabling an enemy ship's electronic systems. If the ship is crewed, the sheet amount of radiation given off by the impact will instantly kill organic creatures.

Lasers could be defeated through the utilization of superconductive armor plating or through the use of sand casters, which would fire dense, reflective particles to disrupt laser beams and particle beams. 

Railguns will probably fire smart munitions, since a shell will need to calculate a ship's trajectory and speed in order to score a hit on a nigh-constant basis. They may also pack nuclear explosive charges, and may come equipped with on-board thrusters for trajectory and direction alterations. 

Stealth is incredibly difficult to pull off in space. As space lacks an atmosphere (and thus particles to bleed heat into), masking your heat signature is rather difficult. Just one second of thrust from a fusion rocket or modern rocket will have you light up on every sensors within several million (if not billion) miles. You could use heat sinks, but hiding yourself for extended periods of time is probably out of the question.

I'm probably missing a lot of info, but this is my two cents using my own knowledge.