I'm an enterprise marketing veteran about to join a small b2b start-up with 5 people that raised 1.5M seed. I'll lead the marketing and sales. What should be a reasonable equity percentage to get?

If you are trying to negotiate your package then I would imagine it's better to work with facts and figures than arbitrary percentages. First, you should find out what the price of that $1.5 million in funding is worth in equity. Once you have that you need to determine what your worth. I think one factor that needs to be known is if they are paying you a salary below your market rate. Another factor is if there is an opportunity cost experience-wise by taking this position. You would determine that by figuring if you were to take a more established position, would you be increasing your earning potential at greater rate than you would be in this role. Essentially, your equity should be worth your loss in current earnings + future earnings + premium for working in a startup due to increased work hours, less holiday time, risk of sudden loss of employment, and higher stress.

Around 1%. Vested over some reasonable time. The reason I say 1% and not 2%, is the fact that NOW you're running both Sales AND marketing. When you guys grow - and I hope you do - the 2 departments will have to split. A new VP comes along, his/her share would be due as well. Good luck!

1-2%.

Impossible to answer without knowing what, if anything, you are getting paid. If it is full market rate then there is a fairly strong argument that you shouldn't get anything. If less, then some small multiple of the value of the gap to market rate converted to equity (e.g. if you are 50k under then 150k worth of shares/options per yeat.