Well there's no MOSFET that's going to the be the best period. You have to consider voltages since that's going to effect other aspects of the transistor. There's also whether you want or need to switch the high side or low side. That determines the required channel polarity.
There's a ton of specs in the data sheets for MOSFETs, but they are used for other things besides user power switches and that's where all those specs become important. For the application here there's only two specs you need to be concerned with, the on-state resistance and gate-source threshold voltage. Often there's a chart in the data sheet that shows on-state resistance versus gate-source voltage. That chart is the only thing you need to look at. Not all MOSFET data-sheets have that chart, but all the later model parts do and the newer parts are the best ones.
Otherwise without looking at that graph, on-state resistances are typically listed at the top of the data sheet for various gate-source voltages. If the only ones listed are at 4.5V and 10V, gate-source threshold voltage may be too high for use with a single cell or parallel cells. The graph tells you one way or the other for sure.
