Adding a list item more efficiently

Scenario:
For one of our requirement we were suppose to add 100s of item to multiple lists and we got into some performance issues.

Solution:
Here's a workaround to avoid the overhead of calling SPList.Items.Add() method.

SPList.Update() must be called to save the newly created item.

Code:

public static SPListItem AddItem(this SPList list){

 SPQuery query = new SPQuery()
 {
 Query = "<Where><Eq><FieldRef Name=\"ID\"/><Value Type=\"Integer\">-1</Value></Eq></Where>",
 ViewFields = "<FieldRef Name=\"ID\"/>"
 };
 return list.GetItems(query).Add();
}