If you don’t like VLC’s primitive appearance or find Totem a bit too buggy, you could always try MPlayer for Gnome.
MPlayer is a movie player that is often overlooked, despite the fact is supports MPEG/VOB, AVI, Ogg/OGM, VIVO, ASF/WMA/WMV, QT/MOV/MP4, RealMedia, Matroska, NUT, NuppelVideo, FLI, YUV4MPEG, FILM, RoQ, PVA files, supported by many native, XAnim, and Win32 DLL codecs, VideoCD, SVCD, DVD, 3ivx, DivX 3/4/5, WMV and even H.264 movies!
It sports a clean and simple interface and some find it more stable then other movie apps. It’s also very lightweight meaning more processor for decoding and not just running.
Grab a .deb below!