What do you want to do with it?
Bullseye accuracy out to 50 yards? I find that for all weights of bullets, AA5 has been most accurate, but only for light to mid-range loads, with Silhouette being most accurate for heavier loadings. For my .40s, I find that 155gn L-SWCs are the most accurate, followed by 175gn L-SWCs. I'm not rich enough to try JHPs and plated have been a total waste of money.
Action Pistol? For minor loads, 180+ gn bullets and almost any fast powder. Be careful though, as .40s&w doesn't have the web strength of 9x19 cases and .40 is known for blowing cases due to over-pressure from fast powders and pressure spikes.
Note: If .40 had been down-graded like 10mm Auto, it would be a 140 PF round.
General plinking? Almost any powder will work. Open your manual and pick one.
Any way, if I had to choose one powder for .40, it would be Silhouette, followed by True Blue and Power Pistol.
Don't like fast powders in this cartridge and really don't like spikey powders like TiteGroup, N310, and Clays.