We have an entire (shared) forum so I say a thread for each release, or at least each series; let's use the space. The classics guys didn't limit themselves to a few threads, so there's no reason we should either.
The advantage of being in with the Classics forum is that two previously separate groups of people can get together to talk about the content, regardless of the format. So if someone wants to talk about the Roger Stern Spider-Man omnibus, there's no reason the Classics regulars can't contribute. And if a Classics person starts a thread about the original Justice League of America issues, then the Omnibus crowd can chime in. There will probably be some aspects of the discussion that don't apply so much to one crowd or the other, but overall, I like that we have a chance to grow the community.
From an Collections perspective, the only things that I think can be limited to single threads are production issues (e.g. Marvel's Omni paper, or DC's binding), collection pics, maybe a bargain alerts thread, upcoming releases, and so on. But in general, I'm going to be inclined to start a new thread, or reply to an existing one that's relevant.
By the way, if anyone's interested, there's a cached version here of an old thread where a Collected Editions forum was discussed before.