60 is perhaps the best unbalanced base in that it is both a superior highly composite (a composite number with more factors less than twice itself) and the least common multiple of all counting numbers upto 6. As long as a fraction only has multiples of powers of 2, 3, and 5, its fractional representation terminates in Sexagesimal (Base60).

The best base of all is balanced ternary (-1, 0, and +1). ¿What does best mean? The number of characters needed to represent a number times the length of the number. This is radix-economy. The radix-economy reaches a minimum at e. Currency would be more efficient if we would take radix efficiency into consideration:

The number of denominations times the number of bills and coins need to make change is lowest at 3. Rather than 2:

0,000.001
0,000.002
0,000.005
0,000.010
0,000.025
0,000.050
0,000.100
0,000.250
0,000.500
0,001.000
0,002.000
0,005.000
0,010,000
0,025.000
0,050.000
0,100.000
0,250.000
0,500.000
1,000.000

It makes morse sense —— ¡or cents! —— to go thus:

0,000.001
0,000.003
0,000.010
0,000.030
0,000.100
0,000.300
0,001.000
0,003.000
0,010,000
0,030.000
0,100.000
0,300.000
1,000.000

I created a DnD-Campaign with a culture using Sexagesimal (Base60). In the distant past, the sapients use electrum for currency until the discovered that it is a natural alloy of copper, silver, and gold. Now they use coins of copper silver, and gold a copper-coin with a denomination of 60 (10 in Sexagesimal (Base60)) is worth a silver-coin with a denomination of 1. A silver coin with a value of 60 (10 in Sexagesimal (Base60)) is worth 1 gold-coin. The highest denomination is a gold-coin with a denomination of 60 (10 in Sexagesimal Base60)). I use radix-economy for the denominations:

Representation of the denominations is in Decimal (Base10):

01
02
06
20
60

Right now, we are the best unbalanced base.