Well, yet again I have them all. Arx Fatalis I have elsewhere, but the others I've gotten from here.
Only Divine Divinity and Warlords Battlecry 3 I've managed to find the time to finish though. I don't know where I'll find the hours to get around to the Arkania games :)
In any case, grab the lot if you can. There's a fair bit of variety on the RPG genre here.

Wow, I guess it's time for Arkania for me. Next time please bring Arcanum into the promo. :)

My dilemma:
Should I get Divine Divinity and Arx Fatalis, or should I get Oblivion Game Of The Year (on sale for 8.50 on steam)?

If i were you I would get both Divine Divinity (great game!) and Oblivion GOTY. Personally I don't like the way Arx Fatalis handles the magic* so that's not an option for me.
* you have to write runes by moving your mouse on the screen

Very welecome those promos, and for my personal taste nice game selection overall.
Beeside the fact im buying more then i can really play :P, for that price im thinking to get the full pack.

Realms of Arkania 1-3 purchased! Thanks GOG.com!

Hell, I am missing only Warlords and i don't know, if it is worth it.

If you like RPG/RTS hybrids, I'd say it's definitely worth it, much more so at the sale price.

Arx Fatails is great, you should give it a run if you like dungeon crawling

Got it with a video card one time (showing off the power of expensive hardware with a game that was 3 years old) and it never really grabbed me

Ahhh, I love RPG promos. I'll definately be buying Warlord and the Realms trilogy this weekend.

This.
WB3 did surprise me in a good way.

Already have all of em :-p

I hope it works as well as your last one did! :D