It depends on the size of your freezer.
I load up when boneless chicken breasts are on sale -Safeway just had them for $1.69 a pound and I got six trays. Ground beef is good to load up on, as is a whole pork loin. If you're into steak, that's a good thing to get a lot of.
Make sure to seal to prevent freezer burn and rotate so that first in, first out happens and you should be good.
We don't eat a lot of fish, so can't comment on that. I think the time it will stay good in the freezer is a lot less than meat.