.Net is bigger than ever, now that .Net Core is a thing. The company I work for has invested in it heavily and everyone using it loves it. Not VB, though. Forget that exists.
Node is a solid choice, so is MySQL, but a lot of developers like PostgreSQL more because it's full of features and lacks very little compared to other solutions. Mongo is a choice for a lot of tutorials, because it's easy to teach with JS. I don't know of anyone using it in production successfully.
GoLang is a rising star and is a pretty fantasic choice. It feels a lot like JS, but with more thought put into the core design and features. It's statically typed, makes threading and async easy, and compiles to a binary. It's considerably faster than most of the other choices.
I guess part of my original question should centre around what CMS I'm going to use to manage the site
this isn't really part of it, this changes the answers entirely. This is a different question entirely than the choice of a backend, because you won't be able to choice either the DB or the language if you want something solid. You won't be working with the DB or backend directly, and the choice isn't your's of what language you use.
It's likely you don't need a CMS unless you're building a site like SitePoint with a lot of editors and people making content. If it's a personal site, you'd be be better off with Gatsby or Hexo. You can host a static site for free with Netlify, or ultra cheap if you have a ton of traffic. Netlify is fantastic.
back in the day I would have used something like an Access database to run a site
This was never really a good idea. If you want something more lightweight and you don't have a ton of users but still want the db solution, then SQLite is a viable solution. It's a single file DB, like Access, but also not insane like Access.