PDF / Office
- Split and merge (http://www.pdfsam.org/) : the swiss knife for PDF, split, merge, transform all your pdf files
- UniPDF (http://unipdf.com/) : want to convert your PDF into Word or images ? That's the tool you need and it's free
- LibreOffice (https://libreoffice.org/) : useless to mention it because it's like the only open-source alternative to Microsoft Office. But you should know that the LibreOffice Writer is able to open a PDF document and to edit it directly even though it generally change the aspect, it is worth a try.
- GreenShot (http://getgreenshot.org/) : the perfect tool to capture your screen, you can transform the image with the integrated image editor, it worths a try, you won't regret it and it is open-source
- ImageMagick (http://www.imagemagick.org/) : I generally use it to create PDF files from images easily and efficiently via the command line. That's like the swiss knife for converting image files.
- Paint.NET (http://www.getpaint.net/) : easy to use, free and efficient. Seriously if you don't want to spend your time watching tutorials or videos, just use this one instead of GIMP.
- GIMP (http://www.gimp.org/): still one of the best for professionals. But you will have to learn how to use it except, maybe, if you used photoshop, I guess there's a lot of similar features.
- Sublime Text (http://www.sublimetext.com/) : if you are a developer, that's just a must have product. Nice features, really fast, ligthweight, a lot of plugins... Seriously forget the old ones that are very heavy (except if you really need them or you are a java developer). I got rid of Eclipse and Aptana Studio for this one but I mainly develop in PHP.
- Notepad++ (http://notepad-plus-plus.org/): difficult not mentionning it. But it's still one of the best. I use it when I have encoding problems or if I want to change very rapidly a basic text file. I don't use it to develop now that I have Sublime Text. If you use python, try not to use it or don't forget to change some parameters in order to avoid the "indentation" problems that are very important inside python.
- Apache directory studio (http://directory.apache.org/studio/) : not lightweight at all but the one with all the features and very stable. I used jxplorer before but seriously it was too buggy... It is based on Eclipse so that's why it is not very ligthweight.
- Jxplorer (http://jxplorer.org/) : I'm mentioning it because it's one of the most used. I guess if you have an old computer and you don't have time neither the bandwidth to download Apache directory studio, you could try this one.
- Strut (https://github.com/tantaman/Strut): my favorite, you can install it on any web server and you will make wonderful presentation with it. It still lacks some features (like self-hosting) but that's just the open-source alternative to prezzi. if you want to try it, just take a look at http://strut.io/. The new version (which means second one) is currently in development, But the first version was pretty complete and I'm not really sure he will keep the new version completely open-source... Wait and see.
- Opale Sup (http://scenari-platform.org/sup/co/01suite_opale.html) : it is more like a new office alternative because it is much more than a tool to make presentation. But I used it for several trainings I've made and I like to create the content in one place and compile it to have the website, the presentation, the opendocument version... Everything I need without (re)doing all the work for each kind of document. By the way, you should try the scenari platform and scenari discovery to make your resume.
- WinDirStat (https://windirstat.info/) : the Windows equivalent of KDirStat. That's the disk analyser usage I use regularly in order to clean up my computer. Easy to use.
- Nginx (http://nginx.org/) : that's a very efficient web server. We generally use it in front of apache as a reverse proxy but you can use it as a normal Web server and, even though it is more difficult to configure, it is one of the most efficient.
General advice : a home server is something you'd like to be fast and to handle a lot of features (owncloud, mail server, etc). So do yourself a favor and try to avoid boards like raspberry pi. Mine is a zotac zbox nano ci320 plus computer, it's smoothly and cheap too.
- YuNoHost (https://yunohost.org/) : the one I use, it has a lot of features and it's really easy to manage especially the mail server. Can't complain right now so I would recommend it. Not to use on a small board
- ArkOS (https://arkos.io) : very promising, you can use it on a small board (raspberry pi, cubiebord, etc). I used it for a couple of months, I got rid of it not because of the functionalities but because my raspberry pi could not handle it anymore... And there was no plan, by that time, to have a version for standard computer, just boards. So I had to change and that's why I finally used YuNoHost (but not on the raspberry pi anymore). This product was amazing so if you have a good board, I would recommend it.
- Univention Corporate Server (https://www.univention.com/products/ucs/) : a really good professional server with a lot of features directly installed. You will have a working Active Directory server (samba 4) and you will have the control over all your servers. That's not really a "Home Server" but you can always use it like that.
- OpenMediaVault (http://www.openmediavault.org/) : difficult not mentioning it. Based on debian, more like a "freenas", it became an self-hosted server with multiple plugins and usage. It always worked like a charm.
I use a raspberry pi for my personnal media center and it works very well. I tried OpenELEC and Rasbpmc, the one I prefer and is the fastest for the rasbperry pi is OpenELEC.
- OpenELEC (http://openelec.tv/) : one of the best. Optimised for your media center but with less plugins and if you want plugins that are not provided, you will have to compile it yourself... But that's the fastest for the raspberry pi.
- OSMC, formerly known as Raspbmc (https://osmc.tv/) : good too, less optimised but based on debian (raspbian) so you'll have almost all the plugins you want.
But prefer the new raspberry pi that will be much more optimized than mine.
- Talend Open Studio (https://www.talend.com/products/talend-open-studio) : just use it, it will give you the opportunity to generate a lot of things. I used it to treat Excel files and insert the data inside a database, generate email signatures, treat / analyse and update your databases. Seriously, for any kind of automated task, it's just the perfect product, easy to use and easy to learn out of the box. It will save you a lot of time, especially for system administrators.
- SoGo : one of the best shared calendar tool and webmail. It is normally easy to integrate in any existing IT infrastructure.
- ansible : simple IT automation, I guess a good system administrator should really use this kind of tools to save him a lot of time and be more efficient.
- Shinken : Nagios fork but better because of its distributed architecture and much improved performances.
- Monit : very simple to use and install. The main idea is to provide a monitoring system for services hosted on a server and relaunch, repair or make a custom script in case a service fails. There is a centralized solution (but not free) called m/monit.
- Zabbix : I used it in 2006 because it was easier to install and use than nagios but I think it's getting a little old.
- Palo (by jedox) : an in-memory business intelligence tool integrated closely with Excel that you'll have to compile yourself.