I do some personal stuff during the day at the office. I end up also doing some office stuff during the evening at home. I am responsive to emails... close to 18 hours a day, but am also not inherently always "on call"... If I get to an email in my personal time, I get to it. If not, I don't, and obviously it depends on how urgent the email is.

The key thing, IMHO, is that you need to find an employer that values you, and knows you put in the amount of work that earns your paycheck. If you're earning your keep, generally an employer should be flexible with how you do it.