Dude, if you want complex languages, take up Icelandic. You'll ADORE conjugating verbs after you try learning weak vs strong noun declension with three genders, multiple SUBGROUPS of genders, and four cases.. nevermind irregular adjectives and verbs out the wazoo. That's on my bucket list, just, yanno, not now. :D
I admire those who learn Oriental languages. I just can't get past the plethora of characters and the slight differences that make such a significant change in meaning. I can read Cyrillic - Russian takes the cake for efficient sentence structure - and some Farsi, but I'm intimidated as hell by Oriental script.
My German is rotting along with my Spanish, but I do speak Norwegian fairly well. Took French in elementary school and that pretty much squashed any desire to pick it up again. But what's awesome about linguistics is what someone else said about Spanish & Italian - it's so cool how everything intertwines and evolves. Eg I've been able to understand some Dutch, Danish, Swedish, and even freakin' Afrikaans because they all derived from the same root.
Oh, yeah, I'm kind of a linguistics nerd. Fair warning, forth --