Is the Elder Scrolls Online standard edition the one to purchase,
or are the DLC worth having as well?
Ehhhhhhhhh.
Disclaimer - I can't remember the stories at all. For giving it a try I imagine just the base game is what you want.
What I will say is that even though you don't
need ESO+, it's far better with ESO+. And, IIRC, with ESO+ you'll get access to all the DLC except the latest chapter.
IIRC the model for ESO is, they release a new chapter which each game version will have in it's name e.g. Morrowind, High Isle, Necrom. Buying the game with that name will give you all the chapters up to that point. But it doesn't give you access to the DLC that's released in that season.
I believe ESO+ gives you access to the DLC including the the current season, but not the latest chapter (necrom in this case).
If you buy an 'upgrade' version, it'll add
only that chapter onto your current account. If you add a full version onto your account, it'll add every chapter up to and including the one you buy.
Here's a list of everything, Chapters are listed on the side.
en.uesp.net
Personally, i'd buy the basic one which includes morrowind (or shop around to see how cheap some of the later chapters are), then grab ESO+ when you play. If you like the game, don't need plus but want some later chapters, you can add whatever version you want on and have access to the chapters up to that release, though you will lose access to the other DLC.
You're best posting in the ESO thread though, they'll know more than me and can correct me if I've got anything wrong and/or fill in any blanks.
Edit: for note, CDkeys has High Isle Collectors Edition for £16 - so IIRC that gives you access to all the collectors edition stuff for every chapter I believe (might only give you High Isle collectors stuff tbh), plus all the chapters excluding the newest one - necrom.