Omnigraffle is phenomenal as well. I believe in using some level of fidelity in mockups. Omnigraffle gives you all the tools to quickly line up elements and try

Omnigraffle is phenomenal as well. I believe in using some level of fidelity in mockups. Omnigraffle gives you all the tools to quickly line up elements and try on layouts / copy really fast. It's the essential tool in my app bar that helps me handle helping 60+ startups with design simultaneously.