My FI and I are planning to do a little registering this weekend. We're registering at Macy's (because I like their Hotel Collection brand), Pottery Barn, and Williams Sonoma. We live together and generally have most of what we could ever want or need so I'm mostly planning to do upgrades, bulk up on linens, and register for some small appliances we don't have...like a really awesome coffee grinder or a larger French Press.
My sister registered at Macy's, Bed Bath & Beyond, and PB. I know I've heard of some people having difficulties with their BBB registries but she didn't have any problems. They seem like a good place to register if you need to pick up a lot of basic items. She used her Macy's registy mostly for serverware, everyday and formal china, stuff like that. She registered for a lot of utensils, and kitchen and bath basics at BBB, and she used PB for some decorative stuff.
@rachelsea53 I think a good place to start is to make a list of things you don't have but think you'll need or would like to have in the future. I don't know if you and your FI live together or not. Do you have any basics at all? No? Then start with a basic every day dining set, pots and pans, a good knife set, etc. Yes? Then consider upgrading some things you do have if they're old, cheaply manufactured, or really worn. Do you like to entertain? If yes, then consider registering for a variety of serverware, like chip and dip bowls, cake stands, platters, serving trays, drink dispensers etc. You can then select the formality depending on the type of entertaining you tend to do...like lots of backyard bbqs? It'd probably be better to stick with bamboo or things like galvanized beverage buckets.
I know I've read that you generally want to double your guest list and make that the number of items on your gift registry(ies). So for example, if you're inviting 100 people, you'd probably want around 200 items on your registry so people have something to choose from and also to ensure that your registry doesn't get entirely picked over as you get close to your wedding date. You DO NOT have to have this many items...it doesn't mean register for a bunch of junk you don't really want...it's just a general guideline.
I think if you and your FI don't live together yet then it wouldn't be a bad idea to start by picking out a bed spread you both like. Use the colors in the bedding you choose to then determine things like bathroom towels, curtains, bedroom and bathroom accessories, etc. For the kitchen, it's better if you stick with white or other neutral colors (stainless steel appliances, etc.) rather than a bunch of colorful things unless you're 100% certain you plan on sticking with a certain color scheme for a very long time.