Me... but using Xubuntu. Ubuntu is too slow for my dino
PC.
Speed wise, improve a lot. Interface is also nicer.
Detection of hardware is just as good as XP. Only difference
between XP and Ubuntu is you need to unmount before plugging out
removable drives. And this sometimes fail quite horribly.
AVG has a Linux version of antivirus, also take a look at ClamAV.
NOD32 is the paid version of antivirus for Linux.
Firewall wise, it's built right into kernel. No need any extra
firewalls. Google it up on how to activate the firewall via
Terminal.
No anti-spyware for Linux for the moment, as far as I know. Neither
do they have any temp file cleaners. The reason is because Linux
files are all over the place, it will take you years to find where
are they.
Drivers wise, wireless is a very bad issue. The support is still
very bad. If you want to try, use Ndiswrapper.
Graphics should have no problems, unless you are thinking of OpenGL
and the likes. They have Beryl and some other stuffs, search the
Ubuntu
forums for it.
Sound card should have no problems.
64-bit PC... some work, some don't. A luck issue. Same for
AMD...
Duo core PCs doesn't seem to be working at the moment... if you are
using one... then I don't know how to help.
Installation of programs - use Automatix for some of the common
programs, like MSN, Yahoo! Messenger, Thunderbird, etc. Included in
Automatix are also some tools to unrar, un7zip, unace your files.
All these archive tools have been ported over to Linux.
Also, if the program you want is not in Automatix, use Synaptic.
It's something like Add/Remove Programs in Windows.
One of the main difference between Linux and Windows is the use of
Command Prompt aka Terminal very regularly. There's no such thing
as EXE, you compile your own programs and install. Also, you will
forever be entering password to install some stuffs.
Common steps will be tar -xvzf file.tar.gz
./configure
make
make install
And erm... downloading of stuffs is sometimes command line too.
Command is wget link
If you need admin rights, sudo command, enter your password.
Like say you need to edit a file. sudo gedit filename.tcl
If you need to get Windows programs to work, install Wine and follow the
documentation.
One thing though... don't just get the basic files, get the
development files as well, because you will almost always be
compiling directly from source codes. Without development files,
you will run into errors.
Common programs are gcc, gcc-dev, g++, g++-dev, python, python-dev,
tcl, tk, tcl-dev, tk-dev, some libraries, the names start with
lib.
And always read their Wiki for instructions. Google is always your
best friend when it comes to solving problems, unless you hit some
rock.