There’s really nothing to convert. The open-source LibreOffice suite can open all your MS Office docs (Word, PowerPoint, Access, Excel). Digital photos and music files need no conversion.
Nor do you need any special capabilities; I’m nowhere near a computer geek, but Linux has come a long way, looks and functions pretty much like Windows now. The only program I haven’t found a really good Linux alternative for is Quicken. So I still keep a Windows computer for that.
If you have even the slightest interest in trying it out, do what I did. Start gradually. Take an old junk computer (who doesn’t have one of those lying around?), and install a Linux distribution on it. Linux can run great on older hardware; it doesn’t have the bloat that Windows has. I have Linux installed on a ten-year-old desktop, and that thing runs better than my much newer Windows 7 computers at work.
Feel free to FReepmail me if you ever want to give it a go.
I'd suggest Gnucash, but it is not the simplest thing to learn unless you're an accountant who does double-enty bookkeeping regularly. Have you thought of using a VM for Quicken? I have one program that I can't run natively in Linux, a simulator for remote controlled airplanes and helicopters (RealFlight). It works great in with vmware-player.