As someone who has a product in this space, some thoughts/ideas:

* Not everyone bills hourly. Include daily and weekly rates.

* It took me a while to figure out how to add a project when wanting to create a time log. Maybe have a "Quick Add" option in the projects dropdown?

* Include currency support. I've found that a lot more companies than I expected price in multiple currencies.

* The "Add Manual" time function could be a little more prominent. Not everyone will want to use a timer.

Best of luck!