The latest stable version of Debian is Debian 9, codenamed Debian Stretch, released on June 17th, 2017. This version will be supported for 5 years, all the way until June 2022! Interesting tidbits about this version include MySQL has been replaced by default with the more open source project MariaDB. Official Firefox and Thunderbird packages are in Debian 9, where previouslly there were similar software but named differently, that naming / branding issue is now no longer confusing users in Debian 9. The developers also want to highlight improvements in the boot process of Debian 9 with UEFI which is greatly improved in this version. Many most of the additional changes are just normal updates and all around improvements of many small things that add up to the latest and best version of Debian.
Debian minor version 9.3 was released on December 9th, 2017.
Debian has a Network Installation media which is the minimum content to boot up the system, from there you can use apt-get after the system is up to add more packages. This is what I recommend for most cases, since you don’t need to download and install such a big image.
The link to download these Network Installation media is here.
Here is a direct download link for the image for AMD64 arch.
If you want to download from one of the mirror’s that might have faster download speeds check this link here.
Here are some direct links to a subset of fast mirrors for quick access from this page:
Americas, Debian Mirror Download
utexas.edu: University of Texas, USA
xfree.com.ar: XFree Argentinia
Europe, Middle East, Africa, Debian Mirror Download
uni-stuttgart.de: Official file server of the University of Stuttgart
icm.edu.pl: University Warsaw, Poland
linux.org.tr: Linux Org, Turkey
Asia Pacific, Debian Mirror Download
xjtu.edu.cn: Xi’an Jiaotong University, China
jaist.ac.jp: Japan Advanced Institute of Science and Technology
poliwangi.ac.id: Politeknik Negeri Banyuwangi, Indonesia
overthewire.com.au: Over the Wire, Australia
debian.org: Main Debian Home Page
debian.org/intro/about: About Debian Page Official
wikipedia.org/wiki/Debian: Debian Wikipedia Page
debian.org/News/2017/20170617: Release Announcement for Debian Stretch
linuxhint.com/debian: Debian Articles on LinuxHint.com