Choose right version

Hi

I worked with SQL Server 3 year ago. Now I would like to study and learn more about this database (now I'm not working with database...just DB2 (Mainframe)... just basic instructions.

My question is about which is the right version for me. I was thinking about Enterprise Edition, but I would like to know about what each version (Express, Web, Standard.... etc... can offer for a beginner like me..?

Thanks