Do some Googling on switching from Windows to Linux. Linux and Windows are 100% different, and just because you're proficient with MS Windows, doesn't mean you'll be proficient with Linux(quite the opposite actually). Your best bet is to stick with Linux native applications, as Wine/Crossover support is very hit/miss(mostly miss). Most of the popular Windows programs have Free alternatives with Linux...
MS Office---- Open Office, AbiWord, StarOffice- All but Star Office are free.
Adobe PS----- The Gimp, and a few others are free(note, Gimp has a steep learning curve)
Media Players---- MPlayer, Totem, Audacity, Xine, the list goes on, all free
Nero------- K3b or GnomeBaker, both free
DVD Ripper- dvd::rip or Acid Rip, both free
AIM, MSN, ICQ, etc--- Gaim/Pidgin, Kopete, and a few others.. All free
Internet explorer--- Mozilla Firefox, Seamonkey, Opera, Konqueror, and a few others, all free
Outlook--- Evolution, Free
Outlook Express---- Thunderbird, Kmail, and a few others, All free
Torrent clients--- KTorrent, BitTorrent, Both Free
What are the hardware specifications of the PC you have? What all do you plan to do with this PC?
go over to http://distrowatch.com/
and take a look at the distros you might consider using, then research them. Almost anything in the Top 10 will be pretty good. Personally, I like Ubuntu 7.04. Its easy to use, fairly newbie friendly, and there's a lot of users, which means support can be easily found with Google, or by simply getting on the Ubuntu channels on IRC. I wouldn't bother with the "LTS" version, as 1, its over a year old, and 2, unless you're planning to pay for support, you'll not really get any benefit from it. If I didn't use Ubuntu, I'd use Debian, then Fedora.
and one last thing, this should be common sense but if you plan on Dual Booting, having Windows and Linux on the same PC, which is probably a good idea till you're not so green with Linux. BACKUP ALL YOUR DATA BEFORE INSTALLING.