This isn't a poll. There's nothnig to debate, nor are opinions relevant.
Emulators are legal as long as the code was legally created. You can "illegally" create an emulator, e.g. including licensed code that you did not pay for. But that's not common.
Downloading copyrighted ROMs is illegal. There is no "delete after 24 hours" rule; that's complete and utter nonsense, and anyone who actually believes that crap is just looking for an excuse to legally pirate.
It's also not sufficient to own the original cartridge. If you have the tools and ability to rip the ROM off the cartridge yourself, that's fine. But if you download it from somewhere, you are participating in an illegal file transer of copyrighted game code. Illegal. I don't know why so many people have trouble with this, it's just common sense. Just because you own a CD doesn't mean you have the right to download all the MP3s from the CD off of BitTorrent, but no one will question your right to rip your own MP3s. Same thing, easy to understand.
As someone pointed out, there are legal ROMS; basically it's homebrew for the emulated console. That's perfectly fine because there's no copyright being enforced, the creator wants you to play it. But the truth is that that's not what people download, they're going after the "real" ROMs...so I always say that downloading ROMs is illegal just to make it easier.
I suppose it's possible that a comercial game ROM has been turned over as freeware, but I know of no game that has done that. It was a rare occurrence with old computer games, and it's even less likely now given the popularity of download sales through channels like the Wii Virtual Console. It's common sense, guys: they're not going to give you for free what they can still make money off of.
I'll leave the thread open for further questions if there are any, but the poll is closed.