If you are doing digital and have an MSO then 2+16ch will do.
Almost all of my work is mixed signal embedded. If I were offered the choice of 2+16 or 4+0, all other things being equal, it's a really tough choice. Probably I'd go with 2+16. Certainly if your intention is parallel busses as you've mentioned in another thread, then definitely, 2+16 over 4+0.
For a while even quite recently I used 2+16 in the lab on a daily basis even though I had 4+16 available, the 2+16 was just a much more easy to use scope (the 2+16 is an Agilent 54642D Megazoom 500MHz/2Gsa/s, the 4+16 is an Agilent 54831D Infiniium 600MHz/4Gsa/s Windows based scope with a boot time to match). I had the 54642D trigger permanently hooked up to a 54622D, so I could get a couple more analogue channels if necessary on the odd occasion. The use case for that was usually when doing switch mode power supplies, although even four channels is often marginal when doing SMPS!
I too was brought up on 2ch CROs, when I could even get my hand on a scope at all that is, and you can do an awful lot with that, and usually you can do all that you need, it's just much more convenient with more channels, there's less manual pen+paper work involved.
It sounds like you may be having a case of what I call "analysis paralysis", and I don't mean that in a negative way, I suffer from this affliction regularly: just keep in mind that any scope is better than no scope at all!