In short – the things you were doing on your commercial operating system (like Windows), can be performed on Linux for free . You can perform all the standard tasks, like:
1. Work on office documents - from word processing and spreadsheets, to databases and presentations (whether they are done with Microsoft Office or with LibreOffice, Calligra Office, Kingsoft Office or similar software);
2. Browse the Internet (a large choice of browsers including the well-known Firefox / Iceweasel, Chrome / Chromium, Opera, to Konqueror, Epiphany, SeaMonkey etc.);
3. Read and send e-mails (with Mozilla Thunderbird / Icedove, Kmail, Evolution and many others);
4. Video conferencing - in a Skype-like manner (with Jitsi, Linphone, Ekiga, ippi and other related utilities, which are cross platform and work also on Windows, Mac as well as on mobile phones and tablets);
5. Image editing and management - bitmap & vector, in formats like bmp, gif, jpeg, png, tiff, psd, dwg, raw etc. (with GIMP, Krita, Fotoxx, Darktable, Pinta, Inkscape and many others);
6. Play music – whether music CDs or audio files on your hard disk in a format of your choice like mp3, flac, ogg, m4a, ape, wav, aac, wma etc. (with Clementine, Rhythmbox, Amarok, Banshee, Musique, Audacious, KsCD, Exaile, VLC and so on);
7. Watch videos – whether DVDs, Blu-Rays or video files residing on the disk drive in formats like avi/dvx, mpeg, flv, mov/qt, mkv, mp4, wmv etc. (with Dragon Player, VLC, Bangarang, Gnome Mplayer, Kaffeine, Totem Videos, SMPlayer, Xine etc);
You can also:
8. Share, open and edit files from other operating systems like Word, PowerPoint, Excel, Access, pdf, compressed files (zip, rar, ace etc.), audio, video, image and other file formats you may come across.
9. Play games - besides many free games installable from the control panel, now Valve/Steam uses Linux as a base OS, and it is possible to buy the well known games at a discount rate of 75% for Linux users!
10. Chat, go on social networks, share files (Kopete instant messenger, Konversation IRC client, Choqok Twitter/Facebook client, Deluge torrent downloader and many others);
11. Burn CDs, DVDs, Blu-Rays as well as traditional back-up of of your files and the system, or create a “ghost image” of the whole hard disk;
12. Edit audio & video files with Audacity, Kdenlive, OpenShot, Rosegarden, etc;
13. Read and buy eBooks in formats for Kindle, iPad, Sony or other proprietary readers (with Calibre etc);
14. Manage your business or private finance with GnuCash, KMyMoney, Skrooge, etc;
15. Programme & build websites (software depending on your specific needs & preferences);
16. Create professional 2D/3D graphics, models and animation (with Blender, for example)
17. Use in an Educational settings (Parley, Kig, Step, Marble, KGeography, Kalzium and many others);
18. Use cloud technology & virtual environment
19. Design and model for CAD/CAM (FreeCAD, LibreCAD etc.)
20. Adapt GUI (graphical user interface) to many languages and to display regional fonts (from Russian, Greek, Portuguese, Hindi, Chinese, Swahili, Japanese, Bengali, Hebrew, Arabic plus many others);
21. Use in any professional setting, from traditional office work to creative design such as 3D and video effects as in movies like ‘Titanic‘, ‘Avatar‘, 'Lord of the Rings', 'The Avengers', 'District 9', 'Contact', the latest 'Godzilla', 'The Hobbit' and others.
There is much, much more. In another words, the things you were doing in a Windows/Mac environment you will be able to do with Linux. Unless there is a software you can't live without, which runs only on that commercial OS, we can't see an obstacle to stop you migrating to Linux. Actually, you may even find that the application you are so dependent on, may be installable on Linux through a “bridge” utility (like Wine software which will allow you to run applications, designed to be installed only on Microsoft Windows, for example).
Finally, may we add – that every software mentioned, as well as thousands more, are totally free and even open source (ignoring Skype and Opera which are not)! So, the nice thing is - that the freedom and enjoyment of our digital world can be ours right now!