Usually any "flat" shoe (without much of hee) that has good support, enough room in the toe box and that is comfortable would be a good choice. Any heel affects the tip of your pelvic girdle and thus, affects your posture, almost always negatively. Also, Earth shoes are not a good choice for 99% of the population, despite their advertising to the contrary. They too affect your posture and are really hard on most people's archilles tendons.
Since having my bouts with back issues, I have found that the least little change in heel height affects how my back feels. Anything with more "heel" than an athletic shoe causes a slight back ache, even a "flat" dress shoe. Also, a totally flat, ballet flat doesn't feel good anymore.
Do you have specific questions? I would say find something that feels comfortable and make that your everyday shoe.
xx M:wave:M