What about Small?!?
Medium and up has been touched upon, but what about small creatures? They have an innate 5" reach, so if armed with a longspear they should have a 10" reach, correct?
3.5's weapon sizing has seriously reduced the effectiveness of small sized PC's. In 3.0 they couldn't wield most reach weapons (w/o monkey grip) because they were large weapons. Now that they can buy small 'sized' variants of those same weapons they should be able to use them to their best effect. Especially if a tiny longspear allows a pixie to not provoke an AOO when they attack with it (as they don't have to enter their opponent's square).