I personally really like W231 and have used a few pounds of the stuff in .44 Special, Magnum and 9mm Luger. I don't like loading anywhere near mx with the stuff though; I prefer to keep it throttled back to something closer to cowboy action loads in the .44-calibers. In the 9mm it only works for me at max charges under 115gr bullets; marginally better with 124s.
One powder I intend to try, just to use up the jug, is Power Pistol. I have probably 1/3-1/2 of a container left from some 9mm experiments. The stuff is awesome to say the least in the Parabellum cartridge. Lots of blast, flash, noise and recoil (comparatively here; it's still not a fire-breathing monster). I suspect Power Pistol and some 200gr bullets would be fun in my .44 Magnum.
Another powder I have looked at is Trail Boss. Given that I prefer to load at light levels for 90% of my shooting, it looks like a good candidate. The downside is that at my local shop it is a little more expensive than the other powders. But I may give it a try anyway.
NRA Master, Highpower Rifle, Across-the-Course
NRA Expert, Highpower Rifle, Mid-Range Prone