As a base Linux distro. I would suggest Linux Mint 4.0 Daryna (Main Edition) http://www.linuxmint.com/rel_daryna.php It is smart, functional and comes with bags of useful software preinstalled.

For Office work you would use OpenOffice which is included with Linux Mint. For details of OpenOffice http://why.openoffice.org/

For Audio editing you would use Audacity which is in the Linux Mint repositories and easily installed. For details of Audacity https://help.ubuntu.com/community/Audacity

For Video editing you would use Kino. You can find Kino here http://linux.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=linux&cdn=compute&tm=71&f=00&su=p284.9.336.ip_p504.1.336.ip_&tt=2&bt=0&bts=1&zu=http%3A//www.kinodv.org/article/static/2

For running Quicken you need to run it via WINE which is included in the Linux Mint repositories. Here is a listing of all releases of Quicken, some work better than others http://appdb.winehq.org/appview.php?iAppId=107

Linux Mint also comes with other very useful software including GIMP which is an alternative to photoshop. To see the useful features of GIMP visit here http://www.gimp.org/features/

Linux Mint 4.0 is based upon Ubuntu 7.10 so much of the software is compatible. There is a more recent release being Linux Mint 5, however I consider 4.0 to be better.

Here is a thorough tutorial on How To Install Linux Mint 4.0 which also gives a full listing of all the software that is included http://www.howtoforge.com/desktop-installation-guide-linux-mint-4.0-daryna

LUg.