I'm really leaning towards Leghorns. Although this year I started White Rocks so go figure! But one of my oldest "survivors" is a wary Brown Leghorn that lays infrequently now but had been a very consistent year round layer and has survived several predator attacks.
I have tried Welsummers twice but the birds seem dumb. and always get eaten by predators. I just lost my last one a few days ago.
Another good breed for me has been Americana/Easter Eggers and their offspring. Rugged, good layers and have not lost one yet. The roosters are always super alert and the hens take to the trees immediately if anything is around.
If you have leghorns and let them free range in winter in Maine, they're more hardy then I would have thought. Every one I know considers them a better warm weather bird and as a result no one I know here in our area of PA has them, unless their birds live in a building in winter.
As a child growing up, my parents had a few that they did not perpetuate because of the flighty temperament.
That said, if someone has his heart set on white eggs I have some California greys and love them. They're production layers, large eggs, never skip a day, are small birds that can forage and avoid predators and have an excellent feed to egg ratio. I do believe leghorns are among the CG's ancestors, but the CG's have a smaller comb that withstands colder weather better. They're not the easiest breed to find but if you can, I highly recommend them.
I also love my EE's and Ameraucanas and buckeye's but the California Grey's can outlay all these and are smaller birds, definitely not dual purpose.