I'll start with mine (feel free to add categories):
- E-mail/calendar/docs: Google Apps standard edition
- Hosting: Slicehost
- Invoicing: Freshbooks
- Analytics: Google Analytics
- Project management: Ta-da list (seriously)
- File-sharing: Dropbox
- Version control: Git
- Backups: rsync + home server
- Instant messaging: Skype
Call me paranoid, but though Google's public motto may be "Do no evil" they're like every company and are after profit at the end of the day. Are you encrypting your e-mails? Is running your own mail server that hard, or does Google Apps offer that much benefit? Would you host your e-mail with Microsoft? Oracle? What really make's Google that different?
I am genuinely curious - Google seems to be treated by large portions of the startup community as if it were some charitable organisation, working for the benefit of man-kind in an open and free manner. Sure, they've done great things - Search, G-Mail, Android and loads of open source work. But they're still a company beholden to their shareholders, selling adverts based on mass data collection. At the end of the day, in my eyes, they're not fundamentally different from Apple, Microsoft or any other hugely funded mega-corp. I wouldn't store my secret sauces with those companies and their ever evolving market plans and TOSs. Am I overly cautious?