My standard gulpfile.

gulpfile.js

'use strict';

var gulp = require('gulp'),
  $ = require('gulp-load-plugins')(),
  beep = require('beepbeep'),
  gutil = require('gulp-util'),
  browserSync = require('browser-sync'),
  reload = browserSync.reload;

var paths = {
    'devassets': 'assets/',
    'devroot': './',
    'prodassets': 'dist/assets/',
    'prodroot': 'dist/'
};

var onError = function(err) {
  beep([0,0,0]);
  gutil.log(gutil.colors.red(err));
};


// --------------------------------------------------------
// Utility Tasks
// --------------------------------------------------------

// Delete 'dist' directory
gulp.task('clean', function(){
  del([paths.prodroot], function(err){
    if (err) {
      gutil.log(gutil.colors.red(err));
    } else {
      gutil.log(gutil.colors.green(paths.prodroot + ' directory deleted.'));
    }
  });
});

// Compile SASS files
gulp.task('sass', function(){
  return(gulp.src(paths.devassets + 'sass/*.scss'))
  .pipe($.plumber({
    errorHandler: onError
  }))
  .pipe($.rubySass())
  .pipe(gulp.dest(paths.devassets + 'css'))
  .pipe(reload({stream: true}));
});

// Validate all Javascript
gulp.task('jshint', function(){
  return(gulp.src(paths.devassets + 'js/*.js'))
  .pipe($.plumber({
    errorHandler: onError
  }))
  .pipe($.jshint())
  .pipe(reload({stream: true}));
});

// Compile HTML files
gulp.task('html', function(){
  return(gulp.src(paths.devroot + 'templates/*.html'))
  .pipe($.fileInclude({
    prefix: '@@',
    basepath: '@file'
  }))
  .pipe(gulp.dest(paths.devroot))
  .pipe(reload({stream: true}));
});

// --------------------------------------------------------
// Build Packaging Scripts
// --------------------------------------------------------

// Package all CSS files
gulp.task('package-css', function(){
  return(gulp.src(paths.devassets + 'css/*.css'))
  .pipe($.plumber({
    errorHandler: onError
  }))
  .pipe($.autoprefixer({
    browsers: ['last 2 versions']
  }))
  .pipe(gulp.dest(paths.prodassets + 'css'))
  .pipe($.csso())
  .pipe($.rename({ extname: '.min.css'}))
  .pipe(gulp.dest(paths.prodassets + 'css'));
});

// Package all Javascript
gulp.task('package-scripts', function(){
  var nonMinified = $.filter(['*', '!*.min.js']);
  return(gulp.src(paths.devassets + 'assets/js/**'))
  .pipe($.plumber({
    errorHandler: onError
  }))
  .pipe(gulp.dest(paths.prodassets + 'js'))
  .pipe(nonMinified)
  .pipe($.uglify())
  .pipe($.rename({ extname: '.min.js'}))
  .pipe(gulp.dest(paths.prodassets + 'js'))
});


// Optimize and package images
gulp.task('package-images', function(){
  var pngcrush = require('imagemin-pngcrush');
  return(gulp.src(paths.devassets + 'images/*'))
  .pipe($.plumber({
    errorHandler: onError
  }))
  .pipe($.imagemin({
    progressive: true,
    use: [pngcrush()]
  }))
  .pipe(gulp.dest(paths.prodassets + 'images'));
});

// Package all root files
gulp.task('package-files', function(){
  return(gulp.src(paths.devroot + '*.*'))
  .pipe(gulp.dest(paths.prodroot))
});


// --------------------------------------------------------
// Keyword arguments that should be used with 'gulp'
// --------------------------------------------------------

gulp.task('build', ['package-images', 'package-scripts', 'package-css', 'package-files'], function(){ gutil.log(gutil.colors.green('Build complete.')); });

gulp.task('watch', ['serve'], function(){
  gulp.watch(paths.devassets + 'sass/**/*.scss', ['sass']);
  gulp.watch(paths.devassets + 'js/*.js', ['jshint']);
  gulp.watch(paths.devroot + 'templates/**/*.html', ['html']);
});

gulp.task('serve', function(){
  browserSync({
    server: {
      baseDir: paths.devroot
    }
  });
  gulp.watch(
    [
      paths.devroot + '*.html',
      paths.devassets + 'css/**/*.css',
      paths.devassets + 'js/*.js'
    ],
    { cwd: paths.devroot },
    reload
  );
})

gulp.task('default', ['clean'], function(){ gulp.start('build'); });