I have created a beautiful bubble chart using Google Charts. Here is a shot of the chart:
Unfortunately, there is no easy way to do this as bubble charts (or anything that uses numerical series for an axis value). You can work around it as explained here.
The general concept is to eliminate your axis labels on the 'main chart' and adjust the gridlines to match the amount of labels you want. Then create an additional dummy chart which shows only the categories, and use that to show the labels.
Unfortunately, this is how it has to be until Google decides to implement the entire ICU pattern set for chart axes...