thing1 : I broke even but that's only because I was in a hurry to sell it since I needed the money for taxes. I would've got at least $2000 if I would've had more time. I still hate that I had to sell that game, it was one of the first things I showed everyone when I showed them my game collection lol.

I'm a beginning collector, so I'm not too knowledgeable yet about rarity and value and whatnot, but I have Dokapon Kingdom on the Wii, which is considered to be rare and valuable for a Wii game because it was distributed by Atlus. However, here in Europe it wasn't Atlus that distributed it, so I'm not sure if it's worth as much as its American counterpart... but it was an obscure game nonetheless. Two friends of mine who are hardcore gamers never heard of it when I showed it to them. Awesome game btw, if you ever come across it, buy it. It's ridiculous, but in a good way. Also a very fun way to screw your friends over or to get screwed over by them yourself : p

On the N64 I have four CIB games (in very good condition) now: Super Mario 64, Donkey Kong 64, Holy Magic Century and Mystical Ninja starring Goemon. I have two limited edition gba sp's, The pink one and the tribal. And in a week, I'll be owning Pokémon Pinball Ruby Sapphire CIB.

For Sega, I have Ristar. Sadly without manual.

And for ps1, I have Vagrant Story that's apparently rather rare.

I don't particularly view value as to do with money. It has a more special meaning to me than that  : ) But I have to say, I'm getting a bit addicted to collecting... which isn't good for my wallet. At all.

Eh,I have to say my most valuable item in games would have to at least be my Skyrim Legendary Edition lol I can't say much on the value of it to really be honest,though for personal value on how much I love this game goes far beyond money in all honesty. If I ever did get rid of it,I hope the next person who owns it won't scratch it up and mess it up to much,seemingly I've done everything to keep the game in mint condition even with the case. Though I guess even with it being the legendary edition of the game with all the downloadable content,I don't think I would be able to get more than at least around 10$ if i'm lucky.

Though back in the day I use to collect consoles,but I got rid of most of em sadly.

I had a N64,Original Xbox,Playstaing,Playstation 2,Gamecube.even a dreamcast! With like only two games that I had for it since I couldn't find anywhere that actually sold dreamcast games locally. Just sadly I either lost the consoles or my brother stole em'. I know for a fact that I sold the GameCube along with it's only pokemon game I had for it since I lost the other one some how.

I really have no idea as far as video games go because I have not appraised them since I started collecting them. I had already planned out what I was going to do with my collection in the future so I saw no sense in checking out how much they are worth. 
I don't  know the worth of any of my stuff but I would guess that my most expensive ones are my older Spiderman and Fantastic Four Comics .... like these for example :
Amazing Spider-Man #3 and up from there. Missing #1, 2, 6, and an original # 15.
FANTASTIC FOUR #5  (1962) <--- earliest one I have for this set. Missing # 1-4.

Not sure what the condition grade would be on them but I would say very good. Most of my comics I have read only once and then they get put up in protective sleeves and stored. 

The most valuable video game in my collection is Xenoblade Chronicles because even though it's only been around since 2012 it's price has went up dramatically recently. Also in my opinion that's the best game ever made for the wii the cutscenes are incredible, the graphics look even better than some PS3 and Xbox 360 games and it has an incredible story.

Since I live in England, I naturally collect PAL games for my PAL consoles. PAL games are normally a little more expensive than the NTSC ones found in the USA, and sometimes the games are rarer in PAL (or even non-existent!) because few or none make it to the UK (Intelli-cube for the PSX never made it to the UK, as well as Action 52 for the NES), so when I say this game is worth a lot, keep in mind it's the PAL version of the game value. Feel free to ebay an NTSC game and then its PAL version and convert the prices (easier to do this on ebay.com and then ebay.co.uk to see the local price change).

My most valuable item in my video game collection so far has to be my Metroid Prime Trilogy game for the wii. It goes for about £80 at the lowest for the complete PAL version, but the NTSC version seems to be worth about $40 (£25). Next would be my PAL version of Sonic Shuffle for the Dreamcast, which in good, complete condition would fetch about £40-50, but again, the NTSC version is about $20-30 (about £15). My most valuable NTSC item is the NES Power Glove, which go for about $100 with a working glove and sensors. I couldn't find a PAL Power Glove, I actually doubt they exist, but I could be wrong. I had to get an NTSC console to actually use it, since it doesn't seem to work on a PAL console at all.

I would say my copy of ninja five-0 which is worth a solid 120 all day.

Or my skyward sword with the gold Wii remote that's another 120. I have quite a few games in my library that

still have a high value

My most valuable item is probably a set of 1999 Japanese Pokemon cards which is valued at $100. My most valuable game is probably the gold edition of Majora's Mask for the Nintendo 64, which is valued at about $70.

My highest value collectible probably is my Lucario amiibo, which is exclusive to Toys 'R' Us, and it will run you about $45 if you get it from eBay, but you might be lucky and can find one in store for $13. My highest value game has to be my Super Smash Bros. 4 Wii U because it is very popular, going for about $45-50 used.