I presently Use Mandriva 2005 LE. I find it does exactly what I want. The big trouble with Mandriva is that the free distribution does not have any 3D graphics drivers. Yes you can DL them but are a pain to get up especially the ATI driver. If you are willing to pay $50.00 USD you can get Mandriva Discovery based on 10.1 release. It has drivers and Browser plugins installed and pre configured. And It works flawlessly.
I would get Acrobat 7.0, Firefox comes with the dist as well as Video editing software, Sound Editing software and Open Office 1.4 (a good Idea woud be to not install an office package at all KOffice or Open Office go to openoffice.org and DL and install OpenOffice 2.0 Beta).
For best windows compatability you can try CrossOver Office from CodeWeavers it will install Windows applications directly to your Linux hard drive and alow you to run them (This includes MicroSoft Office Profesional).
Another plus is that Limewire and EDonky work great and have no Spyware

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For Gaming you can look at Transgameing the have a wine dist that is game specific and can play most Windows games. There are also many ports of Windows games to Linux (great thing is that a lot of the games will have better frame rate than on Windows). :-D