Just download VLC already.
I recently build an HTPC with a Zotac barebone with an NVIDIA ION GPU. The first player I went to was VLC, but I found that it cannot do GPU accelerated HD video. VLC has a checkbox for it in preference, but it doesn't play a 1080p H.264+flac mkv file I have and on a 720p file, CPU usage was high. After much experimenting, I find that smplayer/mplayer and Media Player Classic - Home Cinema will do GPU acceleration right out of the box. Both are free.
Side note. During my experiment, I got so frustrated with Windows 7, I installed Ubuntu 11.10. To my surprise, VDPAU pretty much just works with mplayer, especially mplayer2. I think both the nvidia (proprietary) and nouveau (open source) worked, but my memory is uncertain on this point. VLC under Linux supposedly support the competing VAAPI, which can use VDPAU as a backend, but it did not work. The only reason I eventually switch back to Windows is Netflix and its silverlight addiction, which, by the way, will also not use GPU to accelerate HD video.