There is no one-size-fits-all nail gun.
Literally.
From smallest to largest nails/fasteners, there are :
- pin nailers
- brad nailers
- finish nailers
- coil roofing/siding nailers
- framing nailers
A palm nailer is a slightly different beast. It is more of a pneumatic hammer that is held in the palm of your hand (hence 'palm nailer'

) and taps a loose nail in via repeated hammer blows than a nailer that shoots the fastener in with one single shot/blow.
Define your wants/needs better and someone here will help you spend your money.
And +2 on using full head nails, not clipped head. Not all locales 'accept' clipped head nails, but all 'allow' full head nails as meeting building codes.
Putting up trim? Trim nailer.
Building 'little' stuff? Maybe a brad nailer.
Doing framing? Framing nailer. One of, if not 'the' 'best' is the top-line Hitachi. Whatever the current model number is. Cordless would usually be a Paslode, but they are a bit more expensive to use but don't need a compressor and air hose.
Finish nailer I prefer the 15 gauge instead of the 16 gauge and want an angle mag, not a straight one.
https://www.nailgundepot.com/blog/how-to-choose-a-nail-gun-for-your-project-blog.html
http://www.nailguncenter.com/best-framing-nailer-reviews/