<---- ***not a MM expert (actually, kind of clueless)
Ours is pretty minimal for a true e-fund, but I'm comfortable with it. We have about $6k liquid in an AmEx savings account. All our other savings are in stocks and mutual funds.
I can't really think of a situation where we'd need more on very short notice, and we could liquidate stocks if we really needed to. One of these days I need to get more strategic with our savings and investing, but we haven't been great about setting goals, either.