Avoid white birds of any type.
Are you wanting one breed or a mix of breeds?
If one single breed that's a decent egg-laying, dual-purpose, friendly breed in a lot of colors that can be kept together throughout the year: Orpingtons, Marans, Sussex, Sumatra, Wyandottes, Plymouth Rocks.
- Marans come in a bunch of colors and the majority of them free range well and blend in surprisingly well (I'd avoid splash). Mine have been friendly and ranged well. Hens are good mommies and lay eggs from brick red to milk chocolate brown. Most colors are partridge or birchen based, seemingly. Single combed so watch for frostbite.
- Orpingtons come in a rainbow, a big birds, lay well, profusely fluffy and sweet-natured. Most colors are solid. single combs can have frostbite.
- Sussex are basically Orpingtons with an all-new variety of colors. A jubilee Orp is pretty much a speckled Sussex. Lord only knows why the colors have to get new brand names for skipping breeds. Sussex also come in "coronation" which is one of the prettiest varieties of chicken color I've ever seen (looks like a lavender Colombian). Big bodied, friendly, docile, pretty birds. "Speckled" is a dark red mille fleur, basically, and it's super pretty, too.
- Sumatra are one of the prettier breeds on God's green earth. Come in lots of colors but super hard to find in most of those fancier colors. Can typically be found here in splash, blue and black, and they're all eye candy. Lay light brown eggs like crazy, from what I understand, and weigh a substantial amount more than you'd think (certainly worth eating). Chivalrous, alert roosters who are willing to give it their all defending the ladies. Pea combed and surprisingly cold hardy.
- Wyandottes are the chicken rainbow with a trademark and cherry on top. They have a reputation for stubborn, somewhat aggressive dispositions, but I've yet to have a problem with them. Come in about every color known to poultry. Stunning birds. Mine laid super often and were one of the best layer I had. Fluffy, rose-combed birds. Wily, alert dispositions so they free range well. Roosters are very protective and can be aggressive, depending on breeder.
- Plymouth Rocks may be one of the more perfect chickens, but sadly, like with other breeds, hatcheries have really botched up this breed (like they're doing with most of the breeds on this list). Generally good-natured birds that come in a nice variety of colors (usually white, partridge and barred). Lay and range well, and big enough for the table.
If a mix of breeds: Welsummer, RIR, New Hampshire, Buckeyes, any Brahma color but "light", bigger EEs.
- EEs. I have some fricking huge ones here--seriously, one of these hens has to weigh ten pounds or more. EEs crossed with big breed roosters (usually with the aim of making green layers it seems) get really big. I have a bunch of 1/2 Brahma EE hens here, and they're just monstrous and likely to keep getting bigger as they continue to age. Stands to reason that other EE crosses are likely the same way. They're not a "breed" per se, so all colors are admissible, in their own way. All you're going to get from them is more variety. Wily, spunky, vigorous birds and fantastic layers.
- Welsummers, RIR, NH and Buckeye only come in one color each (red or partridge), but all have the other qualities you're looking for in spades. Welsummers were voted the #1 breed to have in case of a zombie apocalypse. They're spunky, wonderful birds to have around.
- Brahmas can come in a bunch of colors, but most of the ones you see that aren't "light" (Colombian) will be "dark" (silver penciled) or buff Colombian (both are stunning, imho). Watch out they don't get mites or frostbite on their feet because the feathers like to exacerbate both. Incredibly friendly, sweet birds. Never had a mean one. Light Brahmas are pretty popular, which means hatcheries have really screwed them up bad.
Also, try ducks. Pekins are a popular breed for a reason--they get to weight faster and bigger than chickens and lay like crazy. not much yard candy, but they're adorable. Swedish ducks come in two pretty colors, Cayuga in one (but it's gorgeous), Ancona are pretty and lay well. Look into ducks unless you hate the taste of duck meat. Rouen only come in one (but it's a mallard on steroids). Runners come in a rainbow, but they're strictly egg-laying and not worth the effort of eating, from what I understand.
Ask @jchny2000 for more info on possibly acquiring some of these breeds because she's looking to downsize and could use a good home for them. She has or has access to the vast majority of breeds on this list.
I'm no expert but the first breed that came to my mind was the orp. I don't have any, and they aren't really on my list, but they're popular for a reason.
Aren't Sumatras Asian? Seems like I've seen the Asian breeds tend to have a courser texture to the meat. Edible, but maybe not as pleasant as some of the others on the list.
I'm really leaning towards a Welsummer rooster for my next flock roo.
I know you mentioned avoiding white birds, but my Delaware girls are about as alert as any in the flock while ranging. I have good cover in the yard, but they do a great job of hugging cover, not getting too one-minded when feeding, and just generally keeping an eye out. Breeder quality are hard to find, from what i'm seeing, but i'm starting to really isolate them as a favorite and project for the future.
Good reviews of buckeyes have me thinking about a really small sex-link project someday.