I'm partial to Unique and Power Pistol.
I took the Hi Power and Norinco Uzi out the other day and had a ball. The lot of ammo I loaded up was about 50/50 between the two powders. I think it was 250 rounds all together.
Looking back at my load notes, I was using Speer 4062 125 grain round nose lead bullets motivated by 4.5 to 4.8 grains of Unique or 5 grains of Power Pistol with CCI 550 primers. I also had a box loaded up of Lee .358" 105 grain semi wadcutters sized to .356" packed on top of 4.4 grains of Unique with Winchester SPM primers. The brass was mixed head stamps.
Between those two powders, you have quite a few options. The only reason Unique might beat out Power Pistol is the fact that it's the village bicycle of reloading. It will load into just about anything.