How to get Visual Studio Tools for Office ?
If you need help making a decision of which Visual Studio is rigth for you, on this page you can compare the different versions of Visual Studio 2005: http://msdn2.microsoft.com/en-us/vstudio/aa700921.aspx
Basically, when you get the VSTO 2005 you get the Visual Studio Professional IDE with C# and VB.net.
So you don’t have to buy Visual Studio 2005 Professional and VSTO 2005. You just need to get VSTO 2005.
Also, from the compare link you can see that the VSTO 2005 also supports SQL Server 2005 Integration.
But if you alredy have Visual Studio Professional 2005 then you need to get the VSTO Upgrade. VSTO doesn't work on the Express Editions or in the Standard Edition.
Visual APL works with Visual Studio 2005 Standard or better.