coin holder

That's a cardboard flip; it folds over the coin and is stapled, as you can see. The clear plastic is mylar, and won't bother the coin. It does a decent job of protecting the coin, but isn't air-tight. Therefore, the possibility exists that the coin could still be exposed to circumstances which allowed it to tarnish. Many (even most) collectors use them exclusively, and by further protecting their collection - boxing the flips, storing them under proper conditions away from moisture and chemically-charged atmospheres - they'll be okay for decades.

Me, I prefer more secure storage. I tend to handle things more frequently, and there's more turnover in my collection than most. So, I use clear mylar (NOT soft, PVC-added) flips for the short-term, and Airtite holders for longer-term storage. That's the course I advise.

2x2's are great for most collectors in my opinion, you can get the three ring binder pages to put them in and make custom albums for a low cost.

robert18, the three ring binder pages you were talking about to put the 2x2's in...are the holes in the 2x2 certain sizes(preset) or can I make my own? The reason I ask is because I have a great deal of foreign coins and would like to put them in to the binder.

G'day, if you look around, 2x2 come with holes in 2.5mm increments, from 17.5 to 37.5 mm. I've also seem in 39mm, for Crowns & similar, but that's the biggest opening that I've seen. And, at that size, the structure seems a bit flimsy. Everything smaller is fine.
I've found that thick coins don't fit into the size you might expect, and I have to go up one increment.
If you use 2x2, you'd be well-advised to look out for a "flat-clinch stapler" to close them with. I had to hunt around, but I found one for less than $10 in a good stationers.
The albums are great for display: generally, 20 pockets per page.
You can also get smaller "wallets" with six pockets per page: great for taking a few coins to a meeting.
For coins that you want to store, rather than display, I found that well-know brand of tackle-box, manufactured in Illinois, has a model that holds 2x2 just perfectly, with the lid closed. These are robust, and I can stack a few boxes on top of one another.
There are other options for 2x2 storage, but the important thing is to get your coins into the holder, to protect them from drops, bumps, etc.
Peter in Oz