Mine for sure is the free Zoom Player from Inmatrix software.
Why is it good:
1) Works right out of the box.
2) Plays most formats. I don't know if it will pay VIVO format (older internet video format). It also won't play Quicktime format b/c it is closed source. Those are the only 2 it won't play. For me, it won't play real media b/c I don't want their software on my system.
3) A screen capture feature that actually works. This is the first video player that I have ever heard of that actually does it.
4) Works even on molasses slow computers. If you have a high bitrate video and it won't play on your PC, try this, it will work for you. Playing 2.3Mbps takes 30% CPU on my E6600 (on one of the cores). There are even more efficient video players available but their user interface is terrible.
5) Excellent keyboard controls. Has +/- 5 second skip, +/- 120 second skip, and single frame advance/reverse. I have never seen a video player where all of those features actually work. Seek time on skip is typically <0.5 seconds (for video on your hard disk). There are lots more keyboard controls (you can do basically anything from the keyboard), but these are the ones (other than play/pause) I use most often.
Why it is not good:
1) Only for Windows XP and Windows Vista
You can get this from http://www.videohelp.com/tools/Zoom_Player. Be sure to get the 6.00 beta 2 b/c it is better than the current non-beta 5.2 version.
For Linux users the best one is VLC media player. It has many of the features Zoom Player has. It is open source which is a good thing. However, it does not have frame capture (screenshot) feature and also does not have a working single frame reverse feature. The UI is a bit clunkier as well. But you can't beat free, and Linux + VLC media player = Free. I like that the skip amounts are settable in VLC media player. For Zoom Player, the amounts are fixed (5 and 120 seconds for short and long skip).
Edit: Sorry to troll, but Windows Media Player sucks royally. It is one of the worst media players there is. I don't know what the whole deal with unbundling the media player in Europe is, but almost any other media player beats the built in one. Oh yes, this means all versions, both past and (probably) future. Why? It has no features, and may god have mercy on its soul.
What is your favorite video/media player and why?
Winamp, because it's not obnoxiously huge.
For music, I use iTunes because it comes with my computers, I like how it organizes things, and the mini player is just too cute and tiny. For videos, I just use QuickTime. It comes pre-installed on the computers I buy and I rarely watch videos on my computer anyway. Well, I use VLC when it's a filetype that I don't have the right Quicktime plug-ins for, because VLC plays like everything.
My PC is hooked to my 50" HDTV, so I watch videos on my TV. I also watch TV on my TV :)
What I don't like about Winamp:
I listen to podcasts mostly (I'm not a huge music guy). The cure for unprofessional podcasters is the 1.4x playback speed (or 2.0x for VERY unprofessional) in Windows Media Player. Does Winamp have this feature? Where is it? I don't think I've seen a player other than WMP that has this...
So what happened to WMP not having any features? Going back on your word?
OK, it has THAT ONE FEATURE. That's all the credit I'm giving WMP. The feature was introduced in version 7, so version 6 and earlier (Win98 versions of WMP) still suck. I'm sure there's another player out there with this feature and a bunch of others WMP doesn't have.
Edit: A quick google search revealed multiple entries for patents. My guess is makers of other media players didn't include it because of that. Realplayer has it (I don't like RealPlayer-there were rumors going around that they install spyware on your system). WMP has it too and apparently nobody else. The patent applies to digital audio only - var. speed playback of video is allowed. Zoom Player doesn't have this feature though... The only one I have found with it is the free MPlayer. You can get MPlayer http://hhttp://www.mplayerhq.hu/design7/news.html
Edit2: Zoom Player is not that huge. It is a 1.5MB download. The filters you need to enable playback of everything are quite a bit more though. But those don't count-any media player needs those to function.
Edit3: A drawback with Zoom Player: How do I do X? You can probably do it, but you are never going to find the right place in the options dialog all by yourself. It's best to do a google search for [feature] zoom player. That will point you to a forum post (probably) so you can get the help you need. The complicated options dialog is a drawback of any full-featured media player.
I really don't care two shits about what plays what as long as it plays in decent quality and it isn't fucking Real Player.
I use WMP.
Winamp, because the other ones look obese.
I generally use Winamp. With plugins it can play seemingly anything, including the bizarre music files extracted from games. I can also easily record MP3s of midis/anything so I can put them on my crappy MP3 player.
I also use VLC whenever I want to watch a region 2 DVD.
Is there an .mv plugin? Because I've been needing something that can play .mv files.
What filetype is that? Windows Movie Maker? Try using Windows Movie Maker to play the file. Zoomplayer won't do it.
http://filext.com/file-extension/MV
It's not a WMM file, I know that much. I have a game with a seriously kickass soundtrack on my computer, but everything aside from the .exe is in these .mv files.
Try changing the extension to .mov?
I need to know more about the file itself.
VCL player for videos and Itunes for music.
VLC for videos that I have that won't play on any other media player I have, Quicktime for my main stuff, and iTunes for my music, as it comes with my computer. I don't like realplayer.
I did use LimeWire, but I can't take the risk of ruining my newly upgraded computer. I use ITunes most of the time.
Use Frostwire instead. It's open source.
I use Winamp, a friend gave it to me in a CD-RW and when I get used to someting, I don't change it, so it's quite difficult for me to use something else :/. Besides it's small and easy to use.
I use VLC Media Player for videos and Winamp for music. So they're pretty much my favorites.
I dual wield, using ZPlayer mainly and switching to VLC Player when needed.
I dunno the technical details, but I just switch whenever the sound or something of the video doesn't work in ZPlayer.
Video: Media Player Classic/Zoom Player
Music: foobar2000
Dual Wield? I use Windows Media Player, iTunes, and Media Player Classic.
The SEGA Saturn's built-in CD player. With CD-G support (not that I'd have any) various settings and the incredibly boring yet awesome visualisation of a rotating galaxy with little white stars flying at you. And once in a while there's this blocky 3D space ship that flies across the screen doing barrel rolls and stunts. :O
VLC and Media Player Classic. Whatever VLC doesn't like, I play in Media Player Classic. VLC doesn't seem to like MKV files on my computer :\. They lag.
For music, I use WinAmp
I use Windows Media Player for music because it's all I have. Meh.
I tend to shuffle around Winamp, Windows Media Player, DivX, and iTunes.
And RealPlayer, and Quicktime, but that's... not very often.
WMP. I used to use Music Jukebox, but I don't like the new version of it.
Media Player Classic ^_^
And ... VLC XD
I now use Windows Media Player for music.
Right now I'm using WMP and iTunes.
AT THE SAME TIME.
iTunes. Nothing more...
My favorite is GOM Player.
Other than that, I'd pick Windows Media Player
I only have Windows Media Player. I don't really listen to music much anyway and most of the videos I watch are on Youtube. :/
WinAmp is to IE as Songbird is to Firefox.
Songbird.
WinAmp isn't that bad.
Just lacking in, well, everything.
foobar2k
Media Player Classic.
That is all you need.
I mostly use my PS3 to watch stuff. And to listen to music that I don't own on CD.