Know Thyself....
Hi Nicholas!
In truth, there is no one here that can tell you what you need or don't need. They can tell you their experiences, all of which are completely valid for their own purposes. But the real question you have to ask is "what are YOU going to want to do with the airplane?"
Van originally designed the RV line to be simple, performance oriented sport planes. For VFR flying and sport acro, there isn't a whole lot that you need. I have toyed with starting an RV-3 and putting nothing but what I used to have on my old J-3 Cub in for the the way of instruments. This is in contrast to my RV-8 which has a full glass cockpit, three GPS's, Two-axis autopilot, highly redundant electrical system.....in short, everything that I feel I want for traveling, IFR when necessary. There is also nothing stopping me from going up locally in the -8 and flying the heck out of it with some fun aerobatics, like I did yesterday afternoon.
When I start a project, I begin with a set of requirements. I separate the absolute, bottom-line, no-kidding ones from the "nice to haves". I prioritize. And then I start to flesh out what I need in the project to accomplish those requirements. It is an objective, fairly dispassionate process that engineers love, and (many) wives might hate.....and there is nothing that says that when you're done, if you get an answer that you don't like, you can't throw it away and build what you want anyway! But at least you'll have studied all the options.
I tell people that I try not to give advice. I don't know you or your needs. But I will tell everyone that in my opinion, the first thing is for you to figure those needs out. No one can really define them for you.
Good luck on the first of many fun parts - deciding what you want the airplane to do....for you!
Paul