Steve Blank has a long and comprehensive compilation of pretty much every startup resource out there, and I recently heard about Best Vendor which helps you figure out the details of each one.
But, it can take a long time to understand the pro's and con's of each option. Ultimately, if it's free and works fairly well, I just try to pick one fast rather than dive too deep.
Here is what we've been using so far:
- Landing pages: Unbounce (LaunchRock is also popular)
- One-off pages we want to get on the web fast: Weebly
- Domain: GoDaddy
- Internal email: Google Apps for Business
- File storage: Dropbox
- Blog: Google Blogger
- Web Analytics: Google Analytics
- Wireframes: Balsamiq
- Prototyping: Axure
- Social media management: Hootsuite
- Project/bug tracking: JIRA (FogBugz is also popular, but our team is already familiar with JIRA)
- Web services: AWS (of course, since our team is all ex-Amazon)
- Identity: Stormpath (founded by my classmates)