If I were to rank the killstreaks, this would be my order:
1) Orbital VSAT
2) Swarm
3) Lodestar
4) AGR
5) Stealth Chopper/UAV
Now my set-up that I used to use was this:
- AGR, Stealth Chopper, VSAT. This was a very good combo for me, because the AGR would usually get you your Chopper, which would get you your VSAT. All 3 streaks are very close in term of points, only a kill or less apart (if you use hardline). It also provides dominance of both air and ground. If you can manage to get 2 AGR's, whilst having a chopper and a VSAT out, you will absolutely BEAST it, trust me, I speak from much experience. I'd call this set-up
Dominance
After prestiging a few times, and permanently unlocking the Swarm, VSAT and K9 unit, my new set-up was born ;p
- VSAT, K9, Swarm. This is an extremely good set-up for kills and to help play the objective. Whilst they may be very high, if you manage to get them, you won't be disappointed. It's down to you as a player, I can get these with ease, but that's just me, others of you may struggle

But, the VSAT will help you get your dogs with ease, so if you get them and call them out, it will get you your Swarm. I really love this set-up because you don't have to stop to use a streak, you can still run around, alongside your Swarm and K9 and wreak havoc! What's also really good about this set-up is that it's a game changer. The other team either hide or get get killed so quickly they can't defend/play the objective, making it very easy for your team to do just that. I can't tell you how many time that my clan and I have been in close games, or ones that we may lose and I use this streak set-up and we push the other team right back and win the game :p Most of the time they just leave anyway
2 words of advice when running this set-up though:
- Be careful of your Swarm, it can kill you if you get too close to an enemy and if it goes after them at the same time, you're pretty much dead. This can extremely frustrating, because it is very easy to loop over with this set-up and getting killed by your own Swarm is fucking shitty
- I've found that the Swarm often dwarfs the K9 unit, so it's best to call them out separate sometimes. Because the K9 has to run around for it's kills and they are easily killed, they do not get as much kills as they should because the Swarm just rains death from above. So if you wish to maximise your streaks, call them out separate, but never together. (Unless it's ground war or something, but I never play that)
Finally, my latest set-up and the one I currently use:
VSAT, Lodestar and Swarm: I've switched out the K9 purely because it's score requirement, does it no justice. In my eyes, the Lodestar is wayyy better for it's score value, so I choose to use that instead. Also, Lodestar gets you many kills, depending on the other team. Even if the other team are a bunch of Blind-eye noobs, you still manage at least 5-7 kills with it, which gets you close to your Swarm. It works in great combination with the VSAT, because you get +15 per Lodestar kill and +10 for VSAT assist. Everytime you get a kill, you get +25 because you get VSAT assist from yourself as well. Essentially, you're getting +100 points for 4 kills, as long as the VSAT remains out, not to mention any points from your teammates killing any enemies as well

I have to say, this is my favourite set-up so far. You can also choose to manually exit the Lodestar by holding X if you feel it's not doing good enough, which is always good if you want to Run&Gun instead