If you want evergreen, check out conifers - anything that's labelled with 'Fastigiata' is columnar. Check the overall height and spread though, in case it's a giant when full grown. Otherwise, for deciduous, Berberis Red Pillar or Berberis Helmond's Pillar. If you want something really tall, check out Prunus amanogowa, the flagpole cherry - gets about 20/25 feet high and only 6 feet across when mature.