For those of you who like help and mods for strategy games, it's rather useful to register at the Paradox forum where you also need to access some areas.
Revised: Since I have a solution.
If you want to register at the forum, you have to register the game on Steam and then use *that* CD key to register on the forum, rather than one Amazon provides.
Otherwise this is an awesome sale and everything registers on Steam save for one game out of two bundles, which Paradox will fix for you if you file a ticket. You don't have to register at the forums to play, either, so this is just an FYI for those interested in doing so.
Contrary to the other review giving this pack one star, every single title in this pack comes with a Steam key, and they work perfectly.
I really just picked this pack up to get the V2:AHD DLC, but everything else included is a nice bonus. Definitely worth the $10, although the quality on some of the other games is somewhat questionable because, although they are published by Paradox, they aren't developed by them.
I give this 4 stars, and I'd actually recommend the Paradox War Chest over this (unless of course the other stuff in this pack is your kind of thing), simply because it's cheaper and has HOI3, which IS a Paradox developed game,. Again though, this is a very good deal.