My speakers are $11,000 (I paid $6300) my subs are $5000 ($2500 each).
Not sure you can look at it as a ratio as the entry into subs is expensive. For example I would be happy running JBL 590s ($900 a pair now) with my current JL subs but I could also run a pair of Wilson Sasha DAW ($40k) with my current subs and both systems would be fine and integrate well.
I think the real question is how much do you need to spend on a good sub and more importantly how is the crossover handled.
Look at something like the JTR. At $3200 it has to be pretty amazing with great price for performance but it is ugly and no one is going to wants it sitting next to their Rockports…