tagInput.html

<!-- Context should be the object you are tagging -->
<template name="tagInput">
  <select class='tag-input' name='tags[]' multiple="multiple">
    {{#each tags}}
      <option value="{{this}}" selected="true">{{this}}</option>
    {{/each}}
  </select>
</template>

tagInput.js

Template.tagInput.rendered = function () {
  var that = this;
  this.$('.tag-input').selectize({
    valueField: 'name',
    labelField: 'name',
    searchField: ['name'],
    create: function(input, cb) {
      console.log('create tag: ', input)
      Items.addTag(input, {_id: that.data._id});
      var tag =  Meteor.tags.findOne({collection: 'items', name: input});

      if (cb) {
        cb(tag);
      } 

      return tag;
    },
    options: Meteor.tags.find({collection: 'items'}).fetch(),
    render: {
        item: function(item, escape) {
            return '<div>' +
              (item.name ? '<span class="name">' + escape(item.name) + '</span>' : '') +
            '</div>';
        },
        option: function(item, escape) {
            var name = item.name;
            var caption = item.nRefs;
            return '<div>' +
                '<span class="name">' + escape(name) + '</span>&nbsp;' +
                (caption ? '<span class="badge">' + escape(caption) + '</span>' : '') +
            '</div>';
        }
    },
    onItemAdd: function(value, $item) {
      console.log('add tag: ', value);
      Items.addTag(value, {_id: that.data._id});
    },
    onItemRemove: function(value) {
      console.log('remove tag: ', value);
      Items.removeTag(value, {_id: that.data._id});
    }
  });
};

tags.html

<!-- Context is object with 'tags' property -->
<template name='tags'>
  <div class='tags'>
    {{#each tags}}
      <span class="label label-tag">{{this}}</span>
    {{/each}}
  </div>
</template>

This would make for a nice Meteorpad.