Well the best media player of them all is VLC because it plays almost anything, except maybe .swf... not sure though so it might. Definitely check it out. It's exceptionally trustworthy seeing as how it's the most used media player of them all with the exception of Window's Media Player which anyone who knows about VLC almost always chooses it over WMP. If that doesn't play .swf you should try installing Adobe AIR (go to Adobe.com and you can find it there) then search for a FLV viewer there based on AIR. I Can't recall it's name, but i know there was one that played FLV and SWF perfectly. Hope this helps. EDIT :: I Checked and i am almost sure it's called RichFLV (the AIR app) Plus check out some of the other AIR apps, they can do some really cool things that you wouldn't think could easily be done outside of a browser.
Even Windows Media Player can play .flv/.swf files, you just need a good Codecs pack so that your player can "understand" what these files are so it can "play" 'em for you. As loony said, one of the best media player applications that natively understands .flv files is Media Player Classic which comes bundled with K-Lite Mega Codec pack which you can get here: http://www.codecguide.com/download_mega.htm
