From Duplicate Finder:
Youtube Downloader HD is a free tool to download videos from YouTube and save it to your local computer. The videos can be converted to avi video format or to mp4 (compatible with iPod, iPhone). With Youtube Downloader HD you can download High Quality, High Definition, and FullHD videos from YouTube. Main features easy to use just copy video URL from your Web browser and paste to Youtube Downloader HD, no need to use scripts or browser plug-ins, convert downloaded video to various formats, download YouTube High Definition videos and Full HD videos (available on certain videos), Unicode support, Youtube Downloader HD can save movies with Chinese, Japanese, Cyrillic names, and support for big video files.
What's new in this version:
Version 2.9 has fixed the bug "UNABLE TO DOWNLOAD".