What socket should I buy?

Its a very common question that comes to a person's mind while upgrading your PC ?? What socket motherboard (MoBo) should I buy ??? If I buy Socket XXX what processors can I install on it...?? I found an excellent link which gives a very solid FAQ-Answer type information about various Sockets...Check it out here..

http://users.erols.com/chare/cpu_sock.htm