It could be you have multiple problems, … and its important we try and sort this logically.
I note you are trying to use a .asoundrc file. Please, can you explain why? Note this from the URL you provided: "*Neither the .asoundrc nor the asound.conf files are required for ALSA to work properly. Most applications will work without them. They are used to allow extra functionality, such as routing and sample-rate conversion, through the alsa-lib layer. *"A .asoundrc file is not nominally required for users with one sound device and two speakers.
Reference xmms, if you are trying to play mp3 files, you often need to use a version of xmms that is not crippled for proprietary music formats (and mp3 is proprietary). Hence you probably should install a packman packaged version of xmms. Reference youtube, you simply need to install flash-player and mplayerplug-in (the later a packman packaged version).
You should setup your repositories for 4, and only repos (OSS, Non-OSS, Update, and Packman). Remove videolan if you added it. You can find guidance for that here for openSUSE-11.0, which I am guessing that you are using, since you neglected to tell us (and YES, knowing what openSUSE version DOES make a difference).: Repositories/11.0 - openSUSE-Community Again, only set up the 4 I mention and remove others (ie setup OSS, Non-OSS, Update, Packman). Then install xmms, mplayerplug-in, smplayer, flash-player).
Using the OSS, Non-OSS, and Update repos I mentioned, ensure your openSUSE is up to date.
Also, its possible you have a problem with pulse audio. Gnome users in particular tend to have such problems more. Are you a gnome user?
Also provide more information on your PC audio setup (in case there are details you have not mentioned that are important). With your PC connected to the internet copy and paste the following into a gnome-terminal or konsole:
wget -O alsa-info.sh http://www.alsa-project.org/alsa-info.sh && bash alsa-info.sh
When the script completes it will pass you a URL. Please post that URL here.
Also, please copy and paste the following into a gnome-terminal or konsole and post the output here.rpm -qa | grep alsa
rpm -qa | grep pulse
rpm -q libasound2
cat /proc/interrupts
uname -a
cat /etc/modprobe.d/sound