I'd like to install SQL Server 2005 on my primary workstation so that I can begin experimenting with the product. I don't want to get rid of my local SQL Server 2000 instances because it's still our production platform. Can I do a side-by-side installation on my desktop?
As a consultant, my favorite answer to any question is, "It depends," and I'm sticking with that answer now. Can you run SQL Server 2005 side by side with SQL Server 2000? Absolutely. But since you're a SQL Server 2005 newbie, I'm going to suggest that you do something other than perform a side-by-side installation. Have you played with Microsoft Virtual PC (or Virtual Server) yet? If not, it's time to get started. Virtual PC and similar tools from third parties such as VMware give you a clean, safe 'sandbox' in which to experiment. Install Virtual PC, and you'll be able to create separate logical instances that look and feel just like a real machine from an OS and BIOS standpoint. The Virtual Instance resides in file form on your machine, which keeps everything completely separate. The benefits of virtual computing are obvious. Made a mistake during the installation? Who cares? It didn't mess up your real machine.
Yes, you can absolutely run SQL Server 2005 and SQL Server 2000 side by side, but don't forget that SQL Server 2005 also requires newer versions of the Microsoft .NET Framework, which might affect other development work you're doing.
When you're ready to put SQL Server 2005 on a production server, you should carefully plan your side-by-side installation—as you would any upgrade. But don't forget that your primary desktop is in fact a production box from your perspective. Are you brand new to SQL Server 2005 with no clear understanding of the potential gotchas of doing a side-by-side installation? Reading a short Q&A probably won't answer all your questions. Beginning your SQL Server 2005 journey in the protected space of a Virtual PC is a good idea.