wat negatives are you scanning - 35mm? 120? or 4x5?
depending on the max size of the negatives you are scanning, you will have different options. if you are purely 35mm, then flatbeds from canon or epson will be good. once in a while, you may encounter a dedicated 35mm scanner like konica dimage film scanner. if you can find those, it is pretty good.
if you have all the way till 4x5, then you have to consider epson v700 and above series of scanners (not sure if canon canonscan series can do 4x5).