I would go with at least some sort of safe to compliment security/alarms etc.
1.) Even with insurance it would be a PITA/impossible to replace some items.
2.) Equally important to me not losing my guns is to prevent some scumbag criminal from getting them.
They make safes that you assemble, so you can take the parts through your doors and then assemble it in a closet etc. Don't have links handy but they've been discussed on here a lot.
I was going to get a $6-800 gun store safe (cabinet I guess is the right term), but then I thought about my ONE LaRue OBR with a Nightforce scope and figured that gun ALONE cost me about $5000
So I upped my budget and spent about $2500 on a Sturdy. I'd love to have some TL-30 type safe, but feel a lot better with a good heavy steel safe rather than a cheaper safe.
If you have a good alarm, I would vote safe and no insurance. A decent/mid-range safe will take enough time to defeat that with an alarm they won't have time to get stuff out.
Granted if they are in a locked closet AND a locked locker the alarm would likely prevent them the time to break in and get anything.