Playing Music: Winamp - One of the first things I install on a PC. I can't stand windows media player, I don't know how people can use it?
Viewing Pictures: ACDSee - Again I don't like windows picture viewer. ACDSee is alot better.
Fixing Photo's: For once a free Microsoft product that's worth using. Windows Live Gallery is worth having installed to fix your photo's. It has a "fix" button that automatically brightens them up and making it easy to crop them - the only thing I don't like about the latest version is the auto straighten part. Some photo's I don't want to be "straightend" but I havn't found out how to turn this off yet?
Disc Burning & Copying. Nero's the best for this. I wish the "in CD" function would work better as it could be really handy. But never seems to work for me and I just end up losing my data
CDBurnerXP (Despite it's name it works great on win 7 and does do DVDs).
DVD Shrink is a good one to use to back-up your original DVD's.
Alcohol - No not the stuff you drink! This program is handy if you ever get any iso .img files you need to open or if you want to make one from a disc. Forget Alchol. Here's one that's free and works a treat! www.slysoft.com/en/virtual-clonedrive.html
File Compression. WinZip is something you need to have installed. Also WinRar is a handy one.
Video Clips - Making Logo's / Intro's for home videos etc: Bluff Titler.
Install Ubuntu alongside your windows OS. Then if anything goes wrong with a hard drive / internet connection sound or graphics issue just boot to Ubuntu and you'll still be able to get on the net - check emails etc and hopefully recover your files / fix or re-install Windows. It's a life saver. Better still it's Free