DO NOT use SPList directly from methods in webparts & application pages. SPList is a sharepoint object & will instantiate a new SPWeb Object,
if used outside of its parent SPweb object. Always perform operation on SPObjects with in the SPWeb(parent SPObject) context.
We will get the exception with this message : “Please close SPWeb objects when you are done with all objects obtained from them, but not before”
Muchos Muchos Gracias to Jonas for the explanation & pattern in this article