There's nothing wrong with having a safe, and if it is an easy expense for you, I would recommend it. However, since you don't have kids, this is something that you will have to decide if you need. I personally don't have kids and I don't have a safe. I am comfortable with that and I don't think there is anything wrong with it. If someone wanted to give me a safe, I would probably use it to lock up my more expensive firearms, but I would still keep my home defense guns at the ready. I don't want to spend money on a safe. If I have kids it will be one of my first expenses, but until then, I don't feel that I need one.
Realize that if you don't have kids a gun safe is only a guard against theft. It is as necessary or as unnecessary as an alarm system on your home. What I mean by that is that you need to decide what you feel is a necessary level of precaution against theft. If you feel that locking the deadbolt on your house is secure enough, then you probably don't need a gun safe. If you take your home security very seriously, it wouldn't be a bad investment. There really is no right or wrong answer here.
I do want to stress two points, however unrelated they may be from the actual question:
1. First of all, if you have kids you owe it to your family to invest in even the cheapest of gun safes. Not having a gun safe in a household with small children is irresponsible. Now I'm not arguing that it should be law, because I don't like the idea of being forced to do things by the government, but I do think that it is a personal responsibility and as a responsible parent, you should be limiting anyone who is not proficient with firearms from having access to them. If your kids are trained, then that may not be an issue. Personally I think that a good all around way to prevent any accidents is to teach younger children gun safety and to limit their access when unsupervised. Just my opinion.
2. A locked up and loaded home defense gun is useless. I would recommend finding a different solution that promotes safety, but also gives you quick access. Also just my opinion.