Consoles are a bit different than Valve, because consoles are a market completely separate from PC games.
But yeah, its totally worth doing a console version and I hope we can do one. 
Exactly. Personally, I think console gamers make up a larger group that PC gamers. There's no saying that you can't do both, is there?
The way I see it...there will be people out there who don't use Valve or will never hear of Aquaria. Sad fact. Out of that large group, a significant portion has access to an online console. Not everyone, of course not, but a good chunk of it. Even if you lose some of the profits, it'll still be profits that you wouldn't have gained otherwise. Again, the various Steam debates going on in the forum come to mind, so I don't think I need to repeat what's already been said...several times before.
In other words, I'm sure you've already thought of it, but trying to put Aquaria out on the console market certainly can't hurt you. The question is...which console would provide the best support and most accessibility? I'll leave that to you.