Stacking on steam

It's €9,99 as well, so for you at least a good deal regarding price conversion. Very nice value if you want something unique and charming imo, but only if you are interested in a bit of puzzling. So apparently the difference from the console versions is that it "features an all new concept art browser exclusive to the PC version" and Steam achievements.

If you don't have Psychonauts and Costume Quest, go for the bundle.
Psychonauts is easily worth the $10 regular price. I bought it for the XBox years ago and it was worth every penny then.

Doubt it.

That only works with Valve games ( If you already own Half Life 2, and buy the Orange Box, you get a gift copy of Half Life 2)

"Double Fine Bundle: According to our records, you already own one or more of the items included in this package on Steam. If purchasing for yourself, see the Extra Copies support article to determine whether the items you already own can be shared with friends."

Unless specified on the game's storepage, you don't get a new copy.

Sure, let us know. Personally I fell in love with Psychonauts, but they all made me smile while playing. Now I just need to get the other two on Steam as well, got them on XBLA but Gabe Newell is only the 854th richest person on earth so I have to support him a bit.