Both aluminum and carbon arrows have their particular virtues. Depending on what you are looking for out of your arrow will drive which is the best fit for you.

Aluminum generally tend to be initially straighter and more consistent in spine than their carbon counterparts. This will mean a more accurate arrow, however all but the top 1% could never tell the difference. Also after smacking them together in a target butt a couple of times or sending one into a tree or the ground, this will no longer be the case. Aluminums will bend and unless you have an arrow straightener and spend the time using it, will end up being less accurate in the long run.

What aluminum does offer is more weight and momentum than a lighter carbon. It will carry energy downrange better than a lighter carbon, however it will also be significantly slower due to it's higher weight.

Carbon arrows while generally not quite as straight as aluminums or as consistent in spine(unless you shell out for some of the upper end arrows) will be more accurate than you are likely to be able to shoot (especially with a hunting rig). They are generally lighter (faster) than their aluminum counterparts and tend to hold their straightness better. I have heard people say for carbon arrows "It's either straight or it's broken", and while that is not 100% correct, for most archers it is close enough to true.

What you do need to watch out for with carbon arrows is damaged ones. Check each and every arrow after you shoot it. Make sure it is in good condition, not cracked, chafed or starting to splinter. If you see anything that looks like it might be bad put that arrow in the arrow bucket and stop using it. The same can be said for all arrows, however carbon arrows tend to explode rather dramatically when they break during the shot.

There are those that will wave the flag violently for their particular arrow of choce (Aluminum or carbon) and say the other is crap but when it comes down to it, they are both good materials and each have their specific strong points. Pick the material that has the virtues that you most desire and go with that one.

I personally shoot carbons out of my hunting rig and use aluminum for my target bow.