here's a graph that keeps popping up here and elsewhere testing the Panasonic 2900 (also the AW2900 and Redilast 2900...but expect slightly higher resistance and less voltage under load due to the addition of protection circuitry and/or nipple tops on these) and the AW IMR1600 at 2A, basically the equivalent of using a LR atty(@1.7Ω), the AW2600, and a couple others.
i think the AW2600 is the best bet across the board for straight ahead, consistent, no booster vaping, and you can see from the graph that the IMR18650 is a beast out of the gate but the only thing consistent about it is the voltage drop. but in a situation where you need that battery to supply 5 or more (though I would even go as low as 3.5 or 4) Amps continuously, you'll want the AW IMR18650. now if you don't mind using an unprotected lithium cobalt battery like that panasonic (not recommended), you may want to also take a look at the samsung 3000mAh and cytac 2900mAh 18650s which are also relatively cheap and have also tested well...but again, no protection and some of these cells have been found to be refurbished and taken from various sources.