Accounting for time spent

I ask for help in finding a convenient application to account for the time spent.
For me it is important to issue invoices to customers with an indication of the time spent. At first it was an Excel file, but he did not have time to write for me, although it was convenient to count the number of hours. Then it was a piece of paper - it was convenient to keep on hand, but it was not convenient to sum up the clock. And so I came to the programs. After the n-number of hours spent on monitoring the network, I found one program to date that meets all my requirements, namely:

1. Ability to create projects
2. Ability to create tasks
3. Ability to create subtasks
4. Convenient interface
5. Buttons strata, stop, continue in the system tray
6. Export

This program is AllNetic Working Time Tracker . All she has, but the interface is a bit uncomfortable.

Tell me, what is now in this direction? If there is something from domestic developers - great! Price - up to $ 50.

Update: Forgot to mark - Win32 platform