The beater type is going to determine more of the sound than you might think. The density, mass and size of the beater is going to effect how much surface is set into motion, how much air is moved in the drum, and how much force is needed to achieve a particular dynamic level. The bigger beaters will excite more of the low-end of the kick drum.

Beater material will also effect what partials are excited in the overall sound of the drum. Felt beaters are going to have less of an attack to the sound, just as a hard plastic or wood beater would tend to have more "click" or attack to the sound. There are a lot of variables and materials used to make kick drum beaters, so they all are going to be slightly different.

The big question is ... how much of a difference will be realized in the final sound? It may not be prudent to own every beater known to man. But have at least a hard felt beater and a hard plastic or wood beater would be wise. Look at what Drum Workshop does. They have one beater with two different sides; one side has hard felt, the other side is hard plastic.

We could get into the whole physics of sound, etc., but I think that more than what you are really wanting to know.

Think of how the various stick models sound different on your snare. Or how a conga sounds if you play with just your fingers or your entire hand. There are some big differences ... all depending on what you use and what you do with it.

And as always ... this is just my opinion based on my own experiences and research.