And we all know that sooner or later, the bb wolf will come. 
Seriously though, there's a cost-benefit sweet spot for every application. No one should be basing their living on a $10/month host. Parallel web, app, and db servers cost mucho dinero. How much you want/need to spend depends upon the level of risk you want to assume and the cost of downtime. As an example - instead of having an online real-time auto-switchable mirror, can you be down for 5-10 minutes to manually switch to a hot (pre-loaded spare?
Monthly system costs have jump points where getting to the next level of reliability, security, or recoverability requires a significant increase in cost over the existing jump point. There's llittle difference in cost between windows and unix (including Sun) solutions at any given jump point. My list of monthly cost jump points follows - YMMV.
- $5
- < $15
- $30
- $50-$125
- $500-$1000
- $5K
- $10K-$15K
- > $25K