Blue Stripes Combat Jacket: Chestpiece item. Added to inventory following the prologue.
Ultimate Alchemy Outfit: A few alchemical items and gauntlets only. Added to inventory following prologue.
Ultimate Mage's Outfit: A trouser item. Added to inventory following prologue.
Ultimate Swordsman's Outfit: A collection of oils, potions and whetstones that aid with swordplay. Added to inventory following prologue.
Finisher Pack: Automatic, adds new finisher animations.
Mysterious Merchant: In Flotsam, he was on the porch on the left if looking towards the town from where you entered originally. He sold an improved silversword and some other stuff.
Troll Trouble: In Lobinden (village outside Flotsam), find a guy named "Chorab" to get a new quest.
There is additionally a new piece of DLC:
"Barbers and Coiffeuses"
Some traders also provide barbershop services. For a small fee, Geralt can get them to change his hairstyle. Search notice boards for information about barbers and coiffeuses offering services of this nature in a given location. In Flotsam, in Chapter 1 of the game, these services are available from the antique book dealer Einar Gausel. In Chapter 2, look either for Sambor in Henselt’s Camp or for Felicia Cori in Vergen. This apprentice sorceress also provides hairstyling services in Loc Muinne, in Chapter 3 of the game.
From http://witcher.wikia.com/wiki/Witcher_2_Ending not so clear answer to the question and still needs some editing.
-If you decided to kill King Henselt then the meeting in Chapter 3 will change a lot.
-If you let him live, Henselt doesn't only have Upper Aedirn but whole of Aedirn will be given to him as there isn't anyone left to ascend to the Aederninan throne because prince Stennis dies in the ghostly mist.
*If you went with Vernon Roche to save King Foltest's daughter, Anais, and you convince Roche to give the Anais to Temeria. Then Roche wil say that she decided to pick up a sword instead of a doll, and will be a great leader.
*If you went with Roche to save King Foltest's daughter, and you convince Roche to give the daughter to Radovid. She will grow up to marry Radovid and Redania will protect Temeria for the time.
_In the Epilogue, If you went to save Triss yourself, then on your the path to see Letho, You will see Roche saved Anais by himself and is defending her from a bunch of soldiers. You will save him.
-If you decide to save Philippa Eilhart, then you will be able to release dragon from her control. You will not be given an option to kill her.
-If you decide to save Triss instead, then you will be given an option of killing the dragon or leaving it. Iorveth would've went to save Philippa and then get badly hurt by her. You will be given the option to walk away and leave Iorveth to the troops, or attack them and tell Triss to save her. She will say that he is badly hurt and will take months to heal him.
If you saved Sheala de Tancarville, Letho will mention she will be hunted by Royal witch-hunters and die a slow death by them. If you let her die, then Letho will say you showed her mercy.
In both paths, if you save Triss instead, the Council of Sorcerers will still be created, since Triss is the one that pointed out Sile was the traitor.
If you did not save Triss, she will be saved by Lethos, Shilard Fitz-Oesterlen will point out Sile as the traitor and the Council of Sorcerers will not be created, as people will be hunting witches from then on.
If you go with Roche/Iorveth in Chapter 3, then you will walk out with Roche/Iorveth and Triss.
If you go with Triss, you will walk out with Triss only.
Ending Plot Summary
No matter what, Nilfgaard will be on the march north to invade the northern kingdoms. Lethos was employed by Nilfgaard to kill Kings in the northern kingdom to soften them up for the later invasion. Letho used the Lodge of Sorceresses as a cover to kill the Kings because they initally had the same objective.
Lodge of Sorceresses initally only?? wanted to kill Demavend because he was shown to be a weak King. But after his death, Letho used Sorceresses' resources to get in contact with Scoia'tael to kill King Foltest and King Henselt. After the death of Foltest, Letho split with Iorveth and went into hiding, Letho couldn't trust Iorveth anymore as Iorveth and the Sorcereses figured out Letho's true plan.
This looks like the symbol for the "Circle of Vigor" - a hexagon. It boosts your vitality regeneration for 5 minutes.
Likely you visited the Circle of Vigor in the forest outside Flotsam. The Circles all have unusual icons, but potion/oil effects typically look like the potion or oil that grants them.
I couldn't find any particular status screen that lists your effects and the symbol associated with them, sadly.