Here are some PC tools (some have Mac versions) I find indispensable. I'm sure many of you reading this already know of them. I hope the info is helpful to those who aren't aware of some of them. They are in no particular order:
MediaInfo - displays file information including containers, tags, video, audio and subtitles. Adds an entry on the context menu, so you right click on a file to use it. Or it runs in a window and you can drag-drop files into it. You can export the information to text, html, xml, html and MANY more. I find the Tree View the best for individual files, but you can add whole directories (sub directories included) and choose files from a drop down menu. It's free, but you might want to donate something for the project.
dBpoweramp - if you're often in need of changing an audio file from one type to another, this is the Swiss Army knife for that. Select a file or files, right click and select convert, select the file type, and you get a quick conversion (uses multi-cores). There are lots of codecs available on this site for use with this utility.
Everything - this replaces Windows' slow and ever-running in the background search. It is fast! When you add a file, it appears in the Everything window immediately. It can be set up to live in the notifications area of the task bar. There are all sorts of search possibilities. It has a portable version. This is one you'll want to support with a donation. What a time saver!
Bulk Rename Utility - "BRU" is another Swiss Army knife utility that is a file re-namer on steroids. I don't use this often, but when I need to, it is a huge time saver. Did you misspell a file name that is replicated like filenam000 - filenam999 (1,000 files)? Where is the %$@# E in filenam on all 1,000 files?!!! Using BRU, you go to the file directory, select all of the files to be renamed, select the BRU Add section, click insert, enter the alphanumeric(s) you want to insert and the position you want them entered. And you don't have to guess what's going to happen if you make the change -- the New Name column updates as you set up the changes you want. You can change file dates, add a folder name to the file names, replace alphanumerics with other alphanumerics (this is another way you could add the "e" to "filenam" -- search for "filenam" and replace it with "filename"). Copy/Move files, change file attributes, timestamps, and ... enough said -- check it out. Free for personal use, but a donation is appreciated.
Cathy Disk Cataloging Tool - got a lot of data CD/DVD's? Do they have cryptic notes as to what is on them? Do you wish you had a catalog of all the files on all your data disks? Well, this tool is the one for you! You run Cathy, put a CD/DVD in the drive, and it catalogs the files. It's fast and just does the job. Keep on putting the data media in and the catalog grows to include them, too. It's free.
VLC - plays most any video/audio file. General MIDI files, too.
Media Player Classic - plays many media files. There's an announcement that the latest version may be the last one.
OK -- how about adding your favorite utilities to this list. Just comment them in.