Just as an update, I've had the Power Support Anti-Glare Screen Protector on my 4G iPod Touch for a couple of weeks and I'm very, very happy with it. I had the same screen protector on my 1G and I liked the "flat" finish look and especially treasured the feel of the screen with that protector.
I was initially concerned that the anti-glare screen protector would detract from the Retina display on the 4G but my fears were unfounded. The display is sharp and clear. Of course, some folks prefer the reflective "glassy" feel and look so this wouldn't be the screen protector for them. For me, though, I love the clean look (no more fingerprints!) and feel of the Power Support Anti-Glare.
The key is putting it on carefully (isn't that the case with all those screen protectors?) and lining up the "holes" just right. I let my husband do it because he's a perfectionist!