Depends on the shooter, their budget and his intentions IMO, hunter, target etc. For me I'm a hunter 1st, 3D/targets next for hunting practice.
One thing I'll say is that IMHO I'd rather have a lesser quality bow than lesser quality arrows if I have to choose between the two. One who shells out good money for a high quality bow but then pinches pennies on arrows is only cheating himself.
For hunting Whitetails here in Pa. which on the grand scale of game animals are really considered medium sized game, tend to be spooky and jumpy and shots will be relatively close say under 25 yds., I require a blend of speed as well as reasonable weight for ample KE for penetration.
Having 7 bows all set up to shoot the same arrows, shooting year round in leagues etc. my arrows see thousands of shots a year so I also demand an arrow that is tough & durable.
I used to shoot aluminum only and while they performed fine I found I wanted a bit more speed and being a perfectionist of sorts I always insisted on virgin arrows for hunting with aluminum to eliminate the risk of having a slightly bent arrow.
What I wanted was arrow speed that would allow for one pin sighting from 0-30 yds so I made the jump to carbons quite a few years ago.
My arrows now are 380 grains and 400 grains and from all of my bows these arrows shoot at anywhere from the low 260 fps range to the mid 270's. At these speeds I can use 1 pin from 0-30 yds. so it minimizes the guess work and confusion come shot time at the wily old Buck while I get more than enough KE for any Whitetail.
Good quality carbon arrows are extremely durable and unlike aluminum shafts, carbons while they can certainly crack and you do need to check each one regularly for such you don't need to worry about a slightly bent shaft affecting broad head flight when you screw them on as carbons are either straight or they are broken.
Am I implying that Aluminum are no good...absolutely not and I still shoot aluminum from time to time.
The issue is that aluminum arrows are typically heavier than carbon and slower. Yes there are exceptions if comparing the lightest aluminum to the heaviest carbon shafts.
For me to get even close to the speeds mentioned above with aluminum arrows I have to go to the super lite version which have an extremely thin wall thickness and this translates into them being more fragile. I shoot so much that when shooting aluminum shafts it was not uncommon for me to have shafts crack just from the normal oscillation of the shaft over repeated shots.
Building my own arrows for years now to me equally as important as the shaft is using good quality components such as point inserts and nock inserts and nocks. If your point inserts aren't square and/or of inferior quality it may be difficult to get a fixed blade broad head to spin true and fly properly, especially as bow speed increases. Fletching is important as well.
FOC,.......generally for a hunter 11-14% is the optimum range. Typically the greater the speed the better luck one will have on the upper end of this scale.
What one needs to understand is what FOC actually can do to an arrow or what it really means in plain English.
If an arrow had 0% FOC you could balance it on your finger like a kids see saw as each 1/2 would weigh exactly the same.
Trouble is if you shoot an arrow like this it will float and flutter through the air much like a bad-mitten birdie..
.....since each end weighs the same neither end wants to lead.
You can run way over the 14% FOC that I listed and yes while it will likely improve the accuracy and steering capabilities of the arrow the trade off is that by increasing the tip/nose weight of that arrow the trajectory will be affected by the added weight up front so the arrow will drop faster and especially as the shot distance is increased.
This is why FOC is a blend of "both worlds"... adequate enough to "steer & guide" the arrow with utmost accuracy but not too much FOC that it robs to much speed and impacts the trajectory. Always remember that the point steers the arrow while the fletching merely stabilizes and guides the back of the arrow to follow the front end.
FOC is something I explain each year to at least one hunter and often more who calls or comes to me saying..."I've been shooting my field tips great all summer and now that I put my broad heads on while I'm OK L/R they are hitting about 2-4" lower than the field points.
If it's not a tuning issue of the nock height what it often is that few archers realize is that the switch to broad heads actually changed their FOC slightly and increased it causing the arrow to drop faster....
How you may ask since both tips weigh the same
Well..the weight of your broad heads is spread out over a LONGER distance than with your field points and this longer distance results in a slightly higher FOC than with field points by moving the balance point of the arrow forward.
Want to check your arrows ? Take a field tipped arrow and lay a pen or pencil flat on a table and laying the arrow across the pen or pencil trying to balance it evenly so that both ends hang in mid air like a motionless see saw.
When you accomplish this use a felt tipped marker and mark on the shaft where it was sitting on the pen or pencil. This mark is the "balance point" of your arrow.
Now swap out the field tip for a broad head and repeat. You'll find the balance point with the broad head tipped arrow is actually about 1/2"-1" further forward than with a field tip. Exactly how much varies depending on many factors such as tip weight, fletching etc. but all arrows will experience this.
By increasing the FOC slightly and moving the balance point forward you are making the arrow more nose heavy so from the time it leaves the string it drops faster.
Sorry for the long post but as you can tell I really get in to the fine detailed technical aspects of archery.. ;D