If all else fails......
Then just do what you feel is best.
But I am unsure of the way that you are using the term "sample/r".
If you already know this, then totally disregard, and if I'm wrong, then someone let me know!
Basically, every electronic synth that produces sounds is going to be some type of sampler.
The sounds are sampled into the computer of the piece of gear, and when you press the corresponding key or pad on the gear, it produces the sampled audio that was recorded into it's system.
In some cases it is possible to record your own sampled audio data, and use it just like you would with the other sounds.
Is this possible with the MPC? I am not sure because I never really was interested with it (Out of price range, right now!). I probably have the cheapest, non-stereotypical set-up there is, and I can still keep the heads bobbin.
If all else fails, then you should go out and buy all of the things you think you need, or feel you need.
Unfortunately, all the suggestions in the world won't be able to help you, and going to a store to try out a piece of equipment, IN MY OPINION, is somewhat useless, unless the representative and other customers know you will be on it for an extended period of time.
You don't become 1 with a piece of gear through those type of sessions.
So you don't actually see the full potentiality, until you mess with it so much, that when you try to go to sleep at night, you are asking yourself, "What if I tried this?", and BOOM-inspiration strikes, and everyone is familiar with this routine-HA!!!
In this way you learn your current equipment, what you should have gotten, what you don't need, and exactly what to get next time around.
And when you know that, the next time you upgrade, you will be in a powerful position to accomplish what it is you want to do, and how.
My 2 cents.
I-AM