I would definitely Recommend starting here to get some background information for the S5. Link to Everything you need to know
There is not a Honeycomb version, only Froyo and Gingerbread (I don't consider eclair useful day top day). It all depends on what you want to use it for. There are different flavors of ROMs out, and each one is designed to do different things, like Gaming, Stability, CM7, MIUI, Long Battery life, etc.
In my opinion it is best to start with the basics and then try all of them or a few of them to find out what you like and don't like about each one.