I was so stoked when i noticed the map collection extra for sacrifice. Extras like that make me want to buy a game. What are some of the other best extras on GOG so i can check them out?

iL - Sturmovik 1946.
Gosh, the plane guide is freaking huge and contains so much stuff...
It's too awesome to behold... if you enjoy flight simulators or World War II stuff.

The Fear Factory album you get with Messiah has to be the best extra I've gotten

Random mini game for the stronghold games, originally a promo for the stronghold, basically a simple tower defence game that gets hard as crap quickly because you have to manually aim the arrows.
The fallout bible, a quite interesting retrospective on the development of the abandoned fallout 3 project by black isle.
The legendary 200 page manual for apache vs havoc, although you shouldnt buy that unless your a flight sim nerd and prepared to read the whole manual
A map for sacred, if maps are your thing.
I'll post again if any more spring to mind.

The comic book for Beneath A Steel Sky.

Duke Nukem SMS tones :DDD There is a lot of them

Fixed for amplification.

Defiantly, because I'd hate to pay this much for it.
I thought the fallout bible was a Q&A for fans, along with additional content to flesh out the fallout universe? Which one is GOG offering as additional content, because the abandoned 'F3' project was called 'Van Buren'.
I suppose the best extras are subjective, because its all down to the games you buy and how much you like them. Yet, I'm pretty sure that something like a whole additional game or mod is probably the most bang/buck. Like the editor's choice for UT2004.

I get all tingly and excited just from wallpapers and avatars alone

Painkiller soundtrack was quite nice.

B, G&E for it's soundtrack.

I lol'd.

:D Me too.

£98.62 new? That's worse than daylight robbery, that's stripping you naked, taking everything you own, and setting you free in the black part of town. Wait, what am I talking about?