We use WORKetc for essentially everything, as it puts CRM, project management, time tracking, file sharing, invoicing, task management, calendars, and other tools in one google apps integrated collaborative suite.
Not only can we manage WORKetc from Gmail through the contextual gadget, WORKetc also has mobile apps for iPhone and android so it's pretty easy to track time, manage projects, create expenses, update leads, or do other things while out of office.
The cool thing about WORKetc is it lets you track everything your team is doing with an integrated approach, so you can group items together (i.e. timesheets with projects or expenses with to-dos), and track who's making what changes via their profile. There's also a client collaboration portal you can invite unlimited contacts to.