Hearthpwn

Ysera, Gromash, Justicar. Well, I click disenchant button a little to often :/ 

My first golden was iron juggernaut, but I was like fuck it, I need dr. boom

I was Tempted to send Anub'arak to the abyss, but decided better of it. he's already dead anyway... well... sort of...

I did DE Toshley for a Golden Piloted Shredder though. kinda regret it because he wasn't golden and now i have an uneven amount of golden mechs :D

Captain Greenskin before tgt

only legendary i disenchanted was hemet nezzingwary, needed the dust for boom and so far i don't regret disenchanting him, i haven't disenchanted any other of my legends although i quite heavily considered disenchanting mr Token sniper the firelord.

Quote from Wyxoorn jump

My first golden was iron juggernaut, but I was like fuck it, I need dr. boom

Mine too! He now lives on as Harrison Jones. 

The 2 I dusted without having another copy were Millhouse Manastorm and Gruul. I got another millhouse later, never the second Gruul. I needed the dust for ysera at the time, I was very new to hearthstone... that's why I don't regret it, I know it was more than worth it. Nowadays I wouldn't do it because I have a decent collection + extra dust lying around... I hope someday I'll get my 100 gold for having all classic cards... missing 13 legendaries and 6 epics.

Quote from bayo92 jump

I disenchanted Sylvanas when I was I noob. She just had nerfted and she didn't see so much play at that time, and I only played murlocs decks. Luckily, I opened her again just before Naxx, and althout I still played only zoo decks, I knew a little more about the game and I kept it. And now I love her.

that doesnt sound like must of a regret.

you got lots of dust for her at that time,and you got her later anyway.

sounds like a win win to me.

Cho. Not because it is good, but because it would be awesome for gimmick decks. 

I think the "useless" legendaries are actually the worst to dust. This might sound weird, but this is simply because wasting dust on them later is such a pain.

These days I only DE golden legendaries.

Never regret :D

I am lucky-unlucky with getting legendaries that i don't need, i have an almost full collection of legendaries (that i use) just from DEing terrible legendaries, the only legendariy i opened and kept is Ysera, the rest are terrible legendaries like Nozdormu, Onyxia, Bolf, Anub etc etc.

I have dusted 8 golden legendaries and i feel good.

There is no point keeping a card that you won't use just because it's a legendary, trade it for an epic that you need it's far more logical thatn waiting for a future expansion that might make it useful.

Malygos

opened it from a pack(out of 40)...

Ysera I needed 400 dust for a legendary and thought "i never use ysera". I think I crafter Al'Akir.

got rid of golden hogger :(

Pretty much any legendary  I've ever dusted i regretted. You never know when you're going to want to mess around w/ a card and it's too expensive to craft a legendary every time you get the whim.

Malygos, Von Jin (spelling is off I know), Nat (all praise the fish King) and justicar trueheart 

None, because I don't disenchant legendaries. Patience is a virtue :)

Have only de'd Mogor and Icehowl. Only regret is that i held on to Mogor for awhile before getting rid of him. What a piece of trash.