Crystal for Enterprise requires the BI Platform (BusinessObjects Enterprise or Crystal Reports Server) - it is not really a stand-alone application. It's also a Java-based application that doesn't yet have all of the same features as "classic" Crystal - especially when it comes to formatting your data.
By preference, I use classic Crystal almost exclusively. Until the last couple of service packs, CR4E didn't have the ability to connect to tables, stored procedures, or to use Commands - you could only access data through a .UNX universe or BEx query. The CR4E software is 32-bit but its reports run in 64-bit mode inside the BI Platform.
Crystal 2013 is 32-bit software and it runs in 32-bit mode inside the BI Platform, requiring 32-bit database drivers and, if necessary, 32-bit ODBC connections.
-Dell