The 'sound in my head' is the sound of bass as played while I was growing up, which encompasses everything from Elvis to Yes and incorporates LOTS of Beatles and Stones, Motown and glam.
So that's double bass, Hofner Violin and Rickenbacker, and loads of Fender. Keyboard bass doesn't work for me, synth bass is an abomination, and slap bass is pretty much a joke, a party trick that got out of hand.
To my ears, slap isn't bass playing and never will be. It's part of the rhythm section, yes, but it's a part that I try to avoid. It's in the same category as too much cowbell or obsessive use of claves.
Hey ... you asked me, OK?
If I'd been borm in 1966 rather than 1956 then who knows, maybe I'd see (and hear) things differently.