Would you count Emacs as an environment? I usually run that in a tty alongside whatever GUI I'm running. Its great for text editing/programming (of course) but I also use it as a terminal, web browser, email client, IRC client, calendar etc. etc...
I recommend looking over at https://wiki.archlinux.org/index.php/KDE
(ignore the arch linux sepecific information, which is usually just the installation as Arch doesn't alter the packages from upstream much)
You also remind me. With Linux there's plenty of reading material (documentation) and it's actually very helpful unlike Windows' "help pages". I recommend getting familiar with typing man <program name>
. Easily one of the best resources for information.
Linux Mint 12 has a KDE edition, so it shouldn't be difficult to setup KDE, not sure how well it'd integrate though.
Sidenote: The Arch Wiki is perhaps extremely useful for almost any distribution as they use the upstream project. This simply means it's the main developers work without altering almost anything.. Arch doesn't add it's own artwork or code (sometimes they add patches). This makes the Wiki, besides the specific installation procedure, fairly agnostic.
For example, on KDE you might want to disable Nepomuk and Akonadi due to their resource hogging nature. Well the KDE section of ArchWiki can help you alleviate or disable them completely: https://wiki.archlinux.org/index.php/KDE#Nepomuk
PS: I'll stop being an ArchWiki fanboy. But I use it for every other distribution I use as well.
I forgot to thank you earlier for the info about the ArchWiki. I have that bookmarked for future reference now. It does look very nice and helpful.