Advanced Dungeons & Dragons: Treasure of Tarmin for the Intellivision, still in original plastic. That would be my best guess, probably $40.

Secret of Mana, Secret of Evermore (both german version), Terranigma and Doom on the SNES are probablu among my most valuable console games I still have.

I say I still have since I had a Sega Master System II with the game Golden Axe Warrior. The console and all it's games went lost when I moved but later I saw a pricetag of 60£ for that game alone (more than the console btw)

I also have many floppy discs from late 80's/early 90's for my PCs, among them the rather infamous port of Teenage Mutant Ninja Turtles with the impossible jump. I have however no idea what these floppies are worth - or if they even are still in working condition, as the graphics card on my old 486 PC died a few years ago.

Edit:

How much worth are european copies of Chibi-Robo! (GC) and Little King's Story (Wii)?

I was a bit lucky, I bought a few years back while it was still expensive but the hype wasnt as big as it is now and have been for a while. I even sold the box and manual for more money than I bought the complete version for a few years back.

EBGames version of Lunar: Silver Star Story Complete w/o all the extra stuff. The EBGames version was even more limited than the regular Collector's Edition that Working Designs published. Breath of Fire 3 PSX NTSC version is also pretty rare; the game is not available on the North American PSN at all due to licensing issues.

Wasnt cheap. But it was also the PAL version sold in Sweden while still very expensive (roughly 2500 copies released). It has nothing on the NTSC version. Still a four figure game.

Hmm someone who makes a claim like this should be willing to post a picture of them at the very least don't you think? 

No problem maestro. coming right up! =)

https://drive.google.com/folderview?id=0B1akNed2XYVEfkNrRjBzdUdON3JYekMtdHhyTEExRGNEWkg0bXhrU1VZRU51dlpJZlJUWEU&usp=sharing

There yo go :)

Again, that Stadium Events must be worth a fortune. 

Sick collection, though!

Well thank you!

I would love to show off my entire collection but we are in the midst of moving so the place is a mess..  This is also probably the last time I will take a photo of Stadium Events, it's about to change owner because houses are frikkin expensive. But I am not bitter, I have do have extra cart that I am going to save ;)