You might be fine with 170, especially if you anticipate a lot of your guests giving you gift cards or cash. Be sure to keep in mind that while you may have 170 items on your registry, this is counting even the small things that you have registered for. If you registered for a serving spoon, this will count as an item. It is unlikely that a guest or couple will buy you a single spoon as a wedding gift. Also, some people feel uncomfortable giving you gift cards or cash so you’ll have to keep that in mind as well.
Some suggestions that I have would be to register for items that may not normally appear on a registry. My FI and I have registered on Amazon.com. You can register for almost anything through them. Books, movies, games etc, are becoming more popular on registries.
If you don’t want nontraditional items, then think of things that you may need for your living area. You can register at Home Depot for new faucets or sinks, paint, wallpaper etc.
Also, if you will have a home, you may need things like gardening supplies or a lawnmower.
I definitely agree with sweetkate, now is the time to upgrade. Even if you have a lot of things already, you can definitely upgrade. Some brides think that having full registries may appear greedy to guests, but I think it’s about giving your guests options. I am definitely a last minute shopper, and I have been to a couple weddings where there is almost nothing left on the registry and I had to try to come up with something I thought they would like.
If you are taking a honeymoon, a lot of couples are completing honeymoon registries where guests can buy them a night at the hotel or a massage in the spa.
I would go through the stores again and see if there are any items that you wouldn’t buy for yourself, but might still be fun to have.
It’s really up to you. If you feel comfortable with your registry, then leave it as is. Hope this helps!