> Another thing being offered frequently is early exercise. If you join a company early enough you can often afford to exercise all your options outright. If you couple that with an 83B filing you can eliminate your tax liability until you sell your shares.

Even for mature startups you can negotiate a sign-on bonus equivalent to the option grant, and use that to exercise immediately. This is cash-neutral for the company, but the employee will only have to pay the income taxes for the sign-on.