For me it would be the following...
1) Max weight good plastic mid. I like my 180g star coyote for this. I can use it as a mid or a putter even. Being very stable I can use it to shape just about any shot I want for the distance range I like to use it in.
2) A very understable low speed driver. I use my underworld for this role. Gives darn good distance for just about anyone and provides lots of control when there is little to no wind. Can be used for a turnover roller or big anhyzer shots if needed.
3) Slightly overstable low speed driver. For when you need a bit more fade or for high wind scenarios.
4) Stable to slightly understable long distance driver. Basic shot shaping, easy to throw, and good for distance. For newer players stick with speed 9ish discs.
5) One massive overstable driver. Specific for some trick shots like thumbers, rollers, and spike hyzers you need to stick in the ground. These are the disc that just fade hard and slam into the ground if you don't have a big enough arm. I use a predator right now for this, but was using a XXX. My friend uses a Nuke OS for it. Others use a Flick or a Maxx. Any of those will work really. You just want something massively overstable for your normal throwing pattern to produce certain trick effects.
That is pretty much all you need. I find lately I've been using my mids to putt with almost as much as I use my "putters" for the job.
So here is my actual disc list that I would use.
1) Coyote
2) Underworld
3) Teebird
4) Valkyrie
5) Predator
Which is kind of the same discs in my signature