About your requirements, Iceweasel is the supported Firefox derivative (fork), I'm currently running debian as my desktop OS at work and use iceweasel every day, no problem. Gnome3, I think it'll be available on the next stable release, BTW what release are you running? Squeeze? If so I think (IIRC) Wheezy will have it. And finally, about graphics performance/quality, that depends a lot on your graphics card and its driver, but if you think of it like having transparencies, windows closing with fancy effects and so on, you'll need a moderm desktop or compiz (work with gnome2) which I think its available on stable (wheeze).
I have modified a bit your sources.list for wheeze, do you mind to test it and report back?
deb http://http.us.debian.org/debian/ squeeze contrib non-free main
deb-src http://http.us.debian.org/debian/ squeeze main
deb http://security.debian.org/ squeeze/updates main non-free contrib
deb-src http://http.us.debian.org/debian/ squeeze/updates main
# squeeze-updates, previously known as 'volatile'
deb http://mirror.cse.iitk.ac.in/debian/ squeeze-updates main non-free contrib
deb-src http://mirror.cse.iitk.ac.in/debian/ squeeze-updates main non-free contrib
# 3rd party repositories
deb http://packages.dotdeb.org squeeze all
deb-src http://packages.dotdeb.org squeeze all
deb http://www.deb-multimedia.org squeeze main non-free
If you happen to be using wheezy or sid you'll have to change all squeeze ocurrences for the one you're using.
Please, backup your sources.list before replacing it, then test it as follows:
Refresh caches
# apt-get update
Search package
# apt-cache vlc
Install package
# apt-get install <package_name>
If find trouble, please report back with output for those three commands, or at least for the first and last.
Also, if you are already using Wheezy or sid, forget what I said about Gnome3 not being available, it should be there but wheezy is yet to be release and sid is always the development branch.
You can use /etc/apt/preferences to specify which versions you want on a per-package basis.
To have the latest iceweasel version, use (at your own risk) the following configuration files:
/etc/apt/preferences
Package: iceweasel
Pin: release a=experimental
Pin-Priority: 1000
Package: *
Pin: release a=testing
Pin-Priority: 500
Package: *
Pin: release a=unstable
Pin-Priority: 400
Package: *
Pin: release a=experimental
Pin-Priority: 300
/etc/apt/source.list
deb http://http.debian.net/debian testing main contrib non-free
deb http://security.debian.org/ testing/updates main
deb http://http.debian.net/debian unstable main contrib non-free
deb http://http.debian.net/debian experimental main contrib
But beware the the apt_preferences(5) manpage warns
Packages included in a specific release aren't tested in (and therefore don't always work as expected in) older or newer releases, or together with other packages from different releases. You have been warned.
Best Answer
(This might be better as a comment, but as an answer is better formatted)
Comment every line in the
sources.listfile, but:Then, run
aptitude update && aptitude search flashplugin-nonfreeand share the results.It should find the following packages:
In the worst case scenario, you can download the package from the above link and install it through a
dpkg -i <package.deb>command... If you have to deal with dependencies, then that's a different story - good luck!