For me, a little of everything! Whatever suits the song, or what I want to make the song do...

Some of it, just drums and then LH bass and RH whatever, some of it Pianostyle following my piano playing, usually with a fair amount of the ACC muted. Some of it LH chords, RH solo (in fact I LOVE to switch between these two modes on the fly). Some of it sequenced. Some of it, no machines at all (got to remind the audience you CAN play, from time to time!)...

That's the best thing about arrangers... whatever method you feel like, you CAN do it, unlike a WS. But, IMO, no one method works best for ALL situations, and I try really hard not to lock myself into one 'purist' method. The music is supposed to come first, not your 'favorite' method...