Fusion drive or Faster processor

Thanks a lot to all for your answers.

So it seems that I should better put the money I give Apple on the fastest processor I can afford, then max out the RAM and then, if the need appears in the future, buy an external SSD drive, of which the prices are falling anyway, Fusion Drive being a transition solution until those prices actually drop. Am I understanding all of this alright ?

Thanks again.

Sébastien.