Debian is a fine distro, but it’s main strategy is being “the stable distro”. So most software packages are at least a little out of date because they only put the most stable and tested versions of software in their default repos. You can add other repos to get around this if you want the latest and greatest, but most other repos keep their main package list more up to date.
Debian is fantastic if you want to set up a quick and easy home server due to it’s long and solid history, huge user base, simplicity and stability.
That Linux command line book is really, really good. I love how it actually explains the commands and why to use them instead of just being a copy of each commands help document or something.
Congrats on ditching Windows!