Desktop verses General Purpose desktop

Can someone tell me what the differences are between thes 2 install options?

I'm installing RHEL 6.4 and the install is different from what I installed for 5.7 iso via the GUI. 

I'm setting up 4 servers  - a proxy, a web , db and file server. On install i select basic server but this does not install X windows so I have to add/customise the install to include other packages -

On the Desktops option - I'm selecting: General Purpose Debugging and Performance, General Purpose Desktop, Graphical Administration Tools and X Window System.  There is also a Desktop option but I can't seem to fine what the differences are between  Desktop verses General Purpose desktop.

Can someone shed some light

Thanks