When it comes to wood, most people suggest that how you play will have more of an effect than the material.
That said, "brighter" maple and "warmer" rosewood are the common answers.
Common, but not the entire gamut between the two, again, like he said, how you play, and with what kind of strings you put on the bass. Also depends on the pickup. That shoot-out is a good way to gauge. Typically, the MiMs and Japanese standard edition (I believe the '95 is such a beast) have ceramics. The MiAs have Alnicos -- that can have an impact too. They all sound great in their own way, to be fair.
So many variables. If you're thinking of using garden-variety nickel-plated rounds (like D'Addarios, GHS Boomers, Ernie Ball Slinkys, etc...) and you have access to both the maple and rosewood, try them both. See how they feel. Go with your ears as well. Just because you're a beginner, doesn't mean you don't know good sound. ;-)
To give you my example (I'm kinda new to the bass too), I wanted originally a P-bass as well, but being a lefty, my choices were nil unless I got a used Squier Standard P-bass special (which I didn't really want) -- so I had to go for a VM Jazz. I could choose between the obstinately 60s VM Jazz, which was a 3 tone sunburst with rosewood, or a 70s VM Jazz, which was all-maple. The vendor (a local shop here in Montreal) insisted I should go with the maple. I told him I wanted the old-school, mellow flatwound sound. He said to me, trust me, it's better to take away than to add. He meant brightness and punch.
He was right. I am not lacking for low end on my all-maple bass, and it cuts through and sounds very dynamic. It has a certain punchiness I could not hear as well in the 60s version. I now have an inexpensive P-bass copy with a rosewood, and it's nice as well.
Also, maple boards require less care over-all, or at least, they're easier to clean without damaging it, since most of the time the maple is heavily lacquered.