I think I like the new overview and bracket icons, but it's going to take some time before I'm fully comfortable with them. For example, I'm having a hard time differentiating between an NPC ship and a player-operated one, as the grey filling designating NPCs is very subtle. But I'm sure I'll get used to them eventually. They do convey more information at a glance than the old set of icons, to be sure.
I studied the icon listing on the EVE Updates page and downloaded the graphic provided there. Basically, if it's got a pointy top, that thing can shoot at you, and if it has a flat top, it doesn't, in general. There are exceptions, of course - unarmed shuttles are a single chevron, and a capsule is a tiny arrowhead. And drones have their own symbols that aren't universally pointy, as well. So, the pointy-top rule is not completely consistent.
I inverted the colors of the above graphic and printed it out, so now I have a quick-and-dirty reference guide next to my keyboard. Feel free to download this image and do the same for your own use.
I'm sure someone more graphically adept, like Rixx Javix, will make an icon reference chart that is more attractive and readable (nudge, nudge...). (If someone does, please link the location in the comments below.) But for now, this image will have to do.
Hopefully, I won't get blown up while I'm trying to figure out what the heck that thing is that is shooting at me.
Fly safe! o7
UPDATE: Rixx Javix to the rescue! Here's a cleaner version of my crude reference chart. He promises: "I'll have a better one shortly" - I'll post the link when available. Thanks, Rixx!