Buying a ASIC to mine Litecoin would be one of the biggest wastes of money. You would never get ROI, as there are hordes of ASIC owners right now mining and selling to try and gain back the money they spent on buying the ASIC, contributing to lowering the price. Not to mention the plethora of scrypt mining websites that have closed due to Litecoin's constant, non stop, fall in price.