Business analysis is becoming more competitive, predictive, and intelligent with the passage of time, and the same demands more intelligent means of analyzing data. In a corporate environment, there are many discrete business units, each requiring - developing - hosting their own set of applications on a common BI environment hosted in data centers, managed by a centralized operations team. I know of many clients who started hosting their BI environments with the SQL Server 2005 platform, but they forget the fact that this is not the ultimate version. In a shared environment many applications are hosted on the same SQL Server instance, which might be managed using a cluster on SAN volumes.
1) Decouple each service to the maximum extent possible. In raw words, at least do not install all the services like SSIS / SSAS / SSRS all on same box.