When the time comes to burn your playlist, you can use ImgBurn. ImgBurn is a great application, unfortunately lacking the mixing/fading features of Nero. If you use Nero, you will need the free Nero APE plugin to burn Monkey’s Audio (APE) audio files.
To add tags to MP3s, download MP3Tag (it will also edit the tags in files of other formats besides MP3s). MP3Tag can add tags automatically using online libraries.
When you need to find and delete duplicate MP3 files, use Duplicate Cleaner.
You will find online a lot of music files in lossless quality encoding, such as flac, wav or ape formats. If you have a really large collection of music and you need to convert your files to mp3, you can use the Efficient WMA MP3 Converter, a convenient enough application, that will let you convert to VBR high quality mp3 format. I suggest that you set 192 as the minimum rate, and let it go up to 320, in order to have nice audio quality, without sacrificing much of your disk space. The difference between a flac, wav or ape, lossless, encoding with a 320 MP3 encoding, resembles the difference between CD and Vinyl records, while, in terms of space, the resulting MP3 files will be about one third or less of the Flac or Ape files. Check also this post on the best bitrate to encode mp3 files.