I do a bass multisample on the mpc or a synth bass (fantom xr, emu mophatt, triton, analog synth, vst, etc.)
You can do all the above mentioned, but unless you are a bass player, a bass sound on a synth is the easiest way to go.
But; I recomend you purchase mpc tutors bass multisample pack so before you go buy a synth. Why? because it cost like 15 bones. you can load it up in your mpc and see what a bass multisample is all about.
That way you can learn without spending alot of money on a synth, only to find out you where looking for something else.
Alot of people use bass samples and most of them come from a synth, vinyl, or real bass guitar.
If you go to my website
www.blackmarketbeats.com and check out my second to last post?.... I posted up some free bass samples. They are oneshots in the key of "C" so you can use autochromatic on the mpc to make a multisample or you can also use 16 levels.
peace