Depends on your front end language stack. If you're going the LAMP route (Linux, Apache, MySQL, PHP), MySQL, in my opinion, has better hooks into that environment than if you're going with a windows solution.
Personally, it comes down to your skillset (or your developers). MS SQL, by its nature, is a GREAT transactional database that scales very well, but has some underlying performancing that should be done to ensure proper operation. Same goes for MySQL but you can mitigate this somewhat with proper coding, etc.
I'd choose MS SQL if I was using IIS, ASP .NET, etc. I'd choose MySQL if I was using PHP and Tomcat.
hope that helps...
Do you have Windows Small Business Server on you server? If not, I think you cannot use that version of SQL server.
What database is better for you? It depends on things like the level of security you want to implement, the amount of data you will need to manage, the performance level you need, budgeting constraints, etc...
This is the conclusion of a comparison article between these MySQL 5 and SQL Server 2005:
"From a database developer’s perspective, choosing between a MySQL and SQL Server DBMS is a matter of the scale of the database application. For enterprise-level applications, SQL Server wins hands down. It has advanced set of SQL features, superior replication, clustering, security and management tools.
For lower-tier database applications, MySQL can offer the core functionality you require at a very low cost. Some might argue that the latest offering from MySQL has made the open source database system enterprise “worthy”, but this remains to be seen. The advanced functionalities implemented are yet to stabilize and be rationalized across the database engine. What's more, Microsoft has upped the ante with even more advanced features of its own. It’s up to MySQL to rise up to the challenge, but at this point in time MySQL is nowhere near the competitive enterprise field of the more established SQL Server 2005."
Read the full article here
LAMPs are packages that allow you to design and serve web pages, and they include a web server (apache), a database management system (MySql) and a programming language (php, or phyton, or perl), running on a Windows OS.
See the WhatIs WAMP page