My standard BTB Loadout is:
DMR
Plasma Pistol
Plasma Grenades
AA Efficiency
Regeneration shield
Ammo
The combination of Efficiency and Regen-shield is very beneficial. You can pop in and out of cover placing shots, whilst any shots you receive are quickly healed. It takes some time to get used to the disorientating effect of the bubble, but after some time it is no longer an issue. It also helps your fellow Spartans! In that way it is great for long range battle such as on Longbow, Ragnorock and Exile. This load out is also very-very effective against vehicles, and CQC with the plasma pistol is also very effective. The Ammo perk also helps alot, and gives you extra ammo for any power weapons you pick up too!!!
My second load out is for a more offensive approach:
DMR
Storm Rifle
Frag Grenades
Fire Power
Promethean Vision
Explosives
I use this when my team are pushing up on the enemy; such as in the caves on Ragnorock and the enemies base. The closed in areas on exile, the top structure on Longbow etc etc. It is really effect as the combination of the Storm Rifle and a DMR enables me to push or withdraw depending on the the situation. The Frags with the Explosive perk and combined with Promethean vision are great for clearing out enemy concentrated positions - Multikills - Yay! (However i have to refrain from taking on vehicles head on and often find myself running from a Ghost or Hog)
My third Load is designed for the acquisition of Vehicles and power weapons:
DMR
Plasma Pistol
Plasma Grenade
Mobility
Regen-Shield
Ordinance Priority
Mobility enables you to out run team mates (or the enemy) in the race for vehicles, most obviously at the beginning of a match, but also around the respawn time. The DMR and R-S allows me to take out enemies occupying territory in a weapon/vehicle respawn area and then mobility enables me to traverse open areas of the map to acquire the treasures!
Also the Ordinance Priority perk delivers lovely Power Weapons right to your doorstep much quicker! (I may swap the mobility for the ability to re choose ordinance when i get that specialisation or the Vehicle specialisation…im not sure yet)
Fourth is used for very close combat (i very rarely use this TBH):
AR
Bolt Shot
Frag Grenade
Active Cammo
AA efficiency
Explosives
This one i do not use, as i only really play BTB it is not very effective. However if there is an enemy being a general unsporting annoyance such as base camping with the BS, active cammo sniper camping, power weapon corner warming etc etc, i will use this Loadout to slowly sneak up on them and take them out. I dont care if it takes me until the end of the game, i will get them!
The other Loadouts are just what i experiment with, i am currently (and quite unsuccessfully) trying to replace my DMR use with the BR or Carbine so i am just toying around with various combinations to see how i can make use of them. If a game is going very well, or is becoming one sided i will use the carbine and BMR to practice…oh and just started trying to use the Pulse nades…are they any good? I can not seem to use them effectively.