I use lots of canning jars for leftovers, mainly. Dh takes leftover meals to work, so we use those up pretty quickly and I find that they are just fine in jars. I use the food saver for things like grains, flours, etc... (plastic, yes I know, but there really are not other good options for freezing things like that that won't cause damage to the food over a longer period of time) and I also use zip-locks. The thing I'm really careful about w/plastic is just making sure the food I'm putting in isn't really acidic and has had ample time to cool...preferably it has been chilled first. I'm not sure how much of a difference that makes, but I like to think it at least makes some
Oh, forgot to mention that you could wrap things in butcher's paper first, then do something like the food saver for longer-term storage. That way you would get an airtight seal, but the food wouldn't be touching the plastic. I'm wondering how parchment paper would work to wrap? I've never tried it.