Just wondering what are the best/most common UAVs in military service?

I'm not sure you can declare a "best" UAV, per se. The three used by the U.S. that I know of have different capabilities and serve somewhat different purposes - I just read a bit on the UAVs in the latest edition of Popular Mechanics.

The Dragon Eyes is the smallest UAV used by the Army. It's a small five pound machine that is carried in the backpacks of infantryman. It sends real time footage to the troops that carried it and I presume it's really only utilized for small unit operations. It has the advantage of being there when you need it and on your command, just in case a larger more advanced UAV was unavailable.

The next is the 400-pound Pioneer, which scans entire city blocks. It circles higher (1500ft), away from threats on the ground, and is presumably a lot more advancded. This would probably best suit larger units.

The last detailed in the article was the Predator, probably the best known of the UAVs. It circles far higher (5000-15000ft) than the others, and is, once again, presumably the most advanced of the three, and can even carry its on missiles. Downside is that this UAV would probably be the most susceptible to attacks from some sort of AA, due to its larger radar signature.

As for "best", it really comes down to the situation. As for the most common, I wouldn't know. I'd take a guess and say the "Predator" just because of its publicity.

i agree with arclight. there really isnt a best.

I heard UAVs are faulty some of the time and that's a major reason they aren't used more.