There was a review done a while back on a bunch of different battery types. The reason you see those names thrown out is at least in part becuase of this review, those names were the top 3 brands that came out of the review.
AW, Tenergy, TrustFire
AW I think is generally considered the top, but in reality all 3 of those performed almost identically, so going with any of those 3 brands would work just fine for you.
Also just as a warning there were some reports of the UltraFire 3000mhA exploding. Not sure if this was purely a fluke due to that specific battery or if it is a wider issue with all of the 3000mha batteries from UltaFire, but something to keep in mind either way when buying batteries.
Personally I chose to go with the AW out of those 3, no particular reason other than the fact that it seemed to be the most recommended of all brands. But as long as you get one of those 3 brands chances are you will be happy with your battery, I don't think there is anything magical about the AW I just think if you have that many happy customers you are producing quality reproducable results so the chances of getting a dud are most likely lower.