FlashGot is a free Mozilla/Firefox/Thunderbird extension, meant to handle single and massive ("all" and "selection") downloads with several external Download Managers. FlashGot is a Mozilla extension that handles downloads with download managers.(FlashGet, Free Download Manager, Fresh Download, GetRight, HiDownload, InstantGet, Internet Download Accelerator, LeechGet, Mass Downloader, Net Transport, NetAnts, ReGet, Star Downloader, Thunder (Chinese only popular product), TrueDownloader and Ukrainian Download Master [Russian language only] ), WellGet)

Kantaris Media Player can play almost anything you can throw at it - AVI, MPEG, MGEG-AVC, WMV, MOV, MKV, quicktime, matroska, divx, xvid, H264, MP3, WMA, OGG files and more. It can also play DVD's and audio cd's. The player also displays some of the most beautiful music visualizations ever seen. All this is completely free.
It is based on code from Videolan client (VLC) and Bass audio library. The graphical user interface is similar to that of Windows Media Player.