A 1M connection would probably let you websurf for general things.
A 5M connection has enough for a full-HD video stream with a little left over. Plenty of xDSL out there probably runs at that rate still, especially on the fringes.
The 30-50Mbit brackets probably cover VDSL, low rate fibre and some RBI variations as well. That's enough for a few HD streams and other activity all at once. I'd go so far as to say that (currently) that's more than 'enough' I think 'enough' is likely to be somewhere between 5Mbit and 50Mbit/s 'right now'. For a typical household. Remember TV is still available over satellite and terrestrial broadcast, remember then that most internet service is also subject to a bit of time-division.. not everyone's using all of it, all at once, you get economies of scale in terms of the number of users and when they place demand on the system.
You should at least double or treble those numbers to allow for households, not just single users. 😉
I'd suggest you'd probably be needing a reliable 15-20Mbit to run a rural business or home office these days.
And while everyone concentrates on the headline speeds, the typical RBI data cap is already below the monthly "average" for the country as a whole.