We finally decided on XXL Ziploc bags. Each bag easily holds two days of clothes (that's over 60 items plus diapers). Plus they're "squishable" and should fit into nooks and crannies better than the hard totes.
The best price I found was at Soap.com where the bags work out to just over $2 each. (Besides, look how happy the gal on the box is!)
We still plan to use 2 totes: one for food and one for our "swim/jammie" bin since that one has our toiletry organizer that wouldn't fair well in a Ziploc.