The Witcher General

>Where should I start on the books?

In chronological order:
The Last Wish
The Sword of Destiny
Blood of Elves
Times of Contempt
Baptism of Fire
The Tower of the Swallow
The Lady of the Lake

Important thing: the second book, the Sword of Destiny, wasn't translated to English for unknown reasons. You can find fan translations in the links given below.

>Are all the books translated?

All up to the Baptism of Fire, except for Sword of Destiny, which was skipped.
Also, there are complete translations into German, French, Russian, Portuguese and Spanish.

>Are the books essential for the enjoyment of the games?

No, but the books take place before the events of the games and there are many in-game references to the books. It's recommended to read them if you enjoyed the games.

>Does the TW2 do a recap of the first's story?

Yes, it does in one short movie (spoiler alert):
https://www.youtube.com/watch?v=ZHwa-7LBfV4

There is also a short movie explaining what witchers are:
https://www.youtube.com/watch?v=AzfFPONyjSw

>I'd like to play them in order, but all I hear about the first's combat makes me worry that I'll be alienated by it before I get into it.

It's all up to you. Some people don't mind the combat, some can't get over it. But you should give it a shot, especially according to the fact that the plot is, in the eyes of many fans, better than in TW2.

You could always just play it on easy to finish the combat sequences quickly.

Recommended Mods for Witcher 1:
Scabbard Mod - Adds scabbards for the swords http://www.moddb.com/mods/scabbard-mod/downloads/scabbard-mod-v104

FCR - Full Combat Rebalance. Made by Flash who went on to become a gameplay designer at CDPR. Improves the combat drastically while also making it more compatible with lore. http://www.moddb.com/mods/full-combat-rebalance1

Rise of the White Wolf - Improves UI and Textures http://www.moddb.com/mods/the-rise-of-the-white-wolf-powrt-biaego-wilka/downloads/en-rise-of-the-white-wolf-fcr-version

Make sure to install FCR first, then the Scabbard Mod followed by Rise of the White Wolf. Also get hold of the latest patches for these mods which are available on Moddb as well.

Witcher wiki:

http://witcher.gamepedia.com/Witcher_Wiki

Unofficial book translations:

http://forums.cdprojektred.com/threads/16494-Our-Community-Fan-Translations

Map of the Northern Kingdoms:

http://i.imgur.com/BrKZB20.jpg (embed)
http://i.imgur.com/ynRQVob.jpg (embed)

Witcher 3 image gallery:

http://imgur.com/a/S6z1R

Witcher 3 trailers and gameplay videos:

https://www.youtube.com/playlist?list=PLVtML188n-waj2qK6ObUf-bgOw12_Zf5P