Open Source Software
You are familiar with Proprietary Software, if not the phrase. Many of these softwares, from MS Office to Adobe Creative Suite, cost a lot of money, and with all of other life's costs, (Free) and Open source can be helpful.
Ubuntu is the largest Linux Distro, for home users. I did a blog about Linux Distros. Mintu and Lubuntu are decent. I wouldn't recommend Puppy Linux, Zorin, PC Linux, or Ipredia.
Likewise, I've already touched on browsers, and overall, FireFox, WaterFox, and TOR are my preferred browesrs; Yandex, Chromium (mainly for Linux), and maybe Epic, for Chrome-esque browsers.
An alt to MS Office, it mentions Open Office. I have used it, and find it to be a decent alternative. Note, some of the more advanced Power Point animations won't work in Open Office. Libre Office often comes with various distros of Linux, so that may be telling as to which Office is preferred. I got a laptop through a service that caters to NPOs, when I was doing some freelance for one, and the Windows laptop came with Libre.
If you use Adobe Illustrator, I have heard a lot of positive feedback, regarding Inkscape. I have had the chance to use GIMP in Linux and Windows, and find it to be a very good alternative to Photoshop. Some plug-ins, like Eye Candy, may not be available or work, but the program itself still works well. If you're very familiar with Photoshop, there is something of a learning curve, where not all keyboard commands work, or are the same. If you've not used PS, then GIMP will be easy, and as it's free, a good use.
I have tried Blender, on Linux. However, compared to what I've used on Windows, there's a learning curve, and I haven't had time to really get into it.
I used Sea Monkey way back in my XP days. It's sort of a successor to the old Netscape Composer suite. There's the web browser, likewise similar to Firefox. But, like Pale Moon, it's not as compatible with newer sites, addons, etc. My thinking is that the web editor would experience similar issues.
I have used Bluefish, and found it to be adequate, for it's purposes. I found Frontpage (when it ran) and Dream Weaver to be better software, although for freeware, Bluefish does adequate.
As I previously mentioned, I've had my share of issues with Pidgin. You need to already have an account with something (eg, Skype), and trying to use the OTR hasn't delivered any success. A note about Gmail/Google Talk: unless they have changed, you won't be able to use it, unless you are in a Chromium Browser (Chrome, Chromium, and Yandex are where I've gotten it to work).
Thunderbird, which I've mainly used through TAILS, has worked well, as has the GPG extension. It will connect to any mail host that has IMAPP/POP3. I've mainly used it with Yahoo and Gmail. They will give you a warning about "outside software may not be safe," but Thunderbird works great!
I've tried Linphone, and various other SIPs, with no success. They're not very "user out of the box friendly."
If you want to use FTP, such as to a free web host (or even your paid host), then FileZilla is the way to go. Without a doubt, I would give it 5 stars! It's that good. Upload files to a server. Download files from a server. It works, and works well!
For zipping software, I use AlZip (on Windows, and sometimes, using WINE, in Linux). Zip, RAR, JAR, 7zip, and other zip files work flawlessly. You can zip it to the format you want, and password protect it, as well. Like FileZilla, I'd give it 5 stars!
For the Anti-Virus, I use Grisoft's AVG, which has worked very well. I also use SpyBot Search and Destroy. Both of them are highly recommended, although AVG's more freemium, and periodically notifies you that you may like to upgrade for more services. SBS does so, to a lesser degree, less obtrusively. The fun thing is, they recommend to upgrade to provide services, that the other software provides, for free!
I use WordPress.com frequently. Many web hosts will use WordPress.org to implement WordPress options into their site editor abilities. WP's the main reason I don't use many WYSIWYG web editors. I can do most anything I need in WP; although to be a little fancier, I do use WIX.
I've heard GnuCash to be an alterative to QuickBooks/Xero, as well, but haven't used it.
I've only occasionally used Audacity, and for the little I've used it, it works as a good audio program.
I have mentioned Chromium a number of times in various tech posts, and I recommend it over Chrome, although I think Yandex to be the better choice. Likewise, Android, Droid Roms, iPhone, and various mobile Open Sources have been mentioned. While this page talks about iPhone vs Android, that seems to be the stats for the US, possibly North America, and maybe Europe and Australia. This page provides the split, as I sort of thought it was.
Without a doubt, VLC is THE PLAYER TO USE! It comes with some Linux Distros, and most of their software depositories have it. I did have some small issues with it on one LT, but others, including this one, have worked fine. Often, if a video won't play in Windows Media, or other players, it works in VLC! 5 stars!