I agree that you need to get a big one that can be used as a pressure canner or as a water bath canner. I think most foods taste better if you water bath can them, but it is not safe to waterbath most foods. I got the Presto 30 quart pressure canner and it worked great for both. We only do pints for almost everything. In the Presto I can waterbath 9 pint jars and pressure can 18 at a time.
You probably know all this, and others will probably have differing opinions, but as far as accessories:
I recommend you not get that rack lifter for waterbath canning. The jar lifter works just as well, is cheaper, takes up less storage space and reduces the number of jars you can do at one time. We haven't used ours yet. It was a waste.
I'd suggest getting a second stacking rack if yours is deep enough to pressure can more than one row of pints.
You have the food mill taken care of. We use ours mostly for tomato sauces and berries to remove the seeds, but a food mill or a sieve is certainly on my list.
I'd get the funnel for canning. Sure makes it easier and keeps the mess down.
You'll need a decent ladle to fill the jars. Hopefully you already have one.
Now the expensive one. What are you going to prepare the food in for canning? Several products require you to bring the food to a boil. If it is high in acid, you cannot use aluminum. We got a 12 quart stainless steel pot to use and it has made life a lot easier for us. Maybe something else on your Christmas list?
That's all I can think of. Everything else we use we already had. A sauce pan to heat the lids, a kitchen timer, a plastic knife to let the air bubbles out and help pack things tight when required, towels to put on the kitchen counter to work on and cool the jars, a bottle brush for washing jars, and a small plastic ruler to measure the fill height. Different recipes require a difference air space at the top, 1/4", 1/2"or 1". Until you get a good handle on it, I find it useful to actually measure occasionally.
