Like I said, you can never have too much tack. The one problem with that is if it's leather, whether or not you're using it, you have to keep it conditioned and cleaned. I suppose you are buying nylon halters, though, so you don't have to worry about that. My favorite brand of nylon halter is Hamilton. See if you can get one of those. They are much better quality, and the hardware on them is really good.
Oh, yes. While you're buying another halter, look at longe whips. You'll need one sooner or later, and they do come in handy. I got one in that fluorescent yellow, because I noticed that if I tossed it on the ground, some colors blended in so well I had to hunt for it. Get one that's a nice, visible color. Also, it's just a theory, but I believe horses respond better to lighter colors. Before I bought my longe whip, I was using a black one. It worked, but when I got this yellow one, Penny really perked up and responded more. There was a definite difference. Linda Tellington-Jones thinks horses respond to white whips better than dark ones, and maybe she's right.