Startup A seems better, 20k more than market rate sounds really good for a startup, and based on very recent HN threads (but also some bias from badly made personal decisions), it's hard for employees to make money from options so best assume they are worth 0 when making a decision like this. You should get market rate at least, then everything extra can go toward more money or more stock, whichever excites you to work more.

But, there are several other factors that may contribute more to your happiness:

- Who will you report to in each company? How many levels under the CEO/CTO? Politics can suck the life out of you and make you not want to work even when you are making more.

- How many hours of work per week is really expected? Is it corporate 9-5 or startup 9-5 (aka 9-9). Only way to get that info is from people working there.

- How many days of vacation do you get? Is it a loose 'open vacation' policy or do you actually get a fixed number of days that you can take off? Preferably it's the latter.

- What percentage of the company do your stock options make up? Do you know the number of shares outstanding, liquidation preferences, etc.

- What kind of work will you do? Does the domain and the stack interest you? Does this help you reach your career goals?

Hope this helps, good luck!

EDIT: Formatting.