I'm surprised that I haven't been able to find an answer to this, but maybe I'm missing something obvious: is it possible to keep a buffer list per window? I often have around 4 splits, and each one typically serves a specific purpose: CSS in one, JS in another, HTML in a few others, etc.
What I'm probably looking for is a plugin that accomplishes this. Lately I've been using BufExplorer, which does have a setting allowing you to keep its list of buffers per tab, but not per window.
I really like the MRU listing that BufExplorer has, but I find it annoying that it's based on my global list of buffers - what I want is a MRU history per window.