While I'm a service provider, I still buy virtual servers from other providers. Here's a quick list of what I use mine purchased VPS for:
- Distributed DNS servers across the country
- Control panels
- Fail-over for some of our hosted systems (things happen - if our systems go down - we need something to rely on!)
- VPN servers
- File/config/ISO repositories (things that don't matter if they're discovered)
- Game servers
- Personal websites
- Personal VPN server
- "cloud" storage (I greatly dislike the term "cloud" - it has become meaningless) [and again, non-sensitive files/information]
- test platforms