Personal Transactions Map
A global zoom-able map that displays my personal transaction history. Can be over all time or within a specified date range (e.g. the last month).
Can use merchant logos and contact avatars to identify each one. Selecting one would open a dialogue with more information about the transaction (e.g. date, time, value,etc).
I also just opened the D3.js examples page for some extra inspiration.
Bubble Charts
Useful for visualising transactional values in a heirachichal structure, such as Outgoings->Categories->Merchants. At the top level, you could display bubbles for income, outgoings and internal transfers. Selecting a bubble would zoom into display a bubble charts of categories and then again into merchants.
The size of the bubbles correlates to the total value of transactions for each merchant/category over a specified date range.
Could also do the same with how much we receive from contacts and employment, although salary would nearly always be the biggest by far.