We have a joint account, personal accounts each, and are co-signers on the children's savings accounts.
We've mostly used our joint savings of about $15k for me to stay home with the kids for the last 5 years. That said, I get paid in sporadic lump sums a few times a year, and we try to use that as our emergency and fun fund. It's down to about $2k right now, which is worrisome. We do have a $7k line of credit, if we really needed it.
We have no debt except for a mortgage on a 1 bedroom suite that we rent out. That is our retirement savings. My partner is a chef, and I'm a writer, so we're not going to have any RRSPs at this rate. We do hope to buy one more rental property when we can afford a large down payment.
I like to have at least $10k in savings at any time, and it's unusual that we only have $2k, but that's mostly because I'm starting a new business and have dipped into that for start-up funds.
As for a nest egg for if anything goes pear-shaped? Not really. I could bolster my personal account, but we lived pretty close to paycheque to paycheque and that'd be difficult. The line of credit is on my personal account though.
Interesting question, Mamazee!