I'd go with a regular straight. Shavettes use either single or double edged blades, and finding the right blade takes some time...some are sharper than others, and it can be tricky to narrow down problems in technique or blades if you're first learning.

A nice 5/8 or 6/8 blade from the Classifieds here will get you started for a reasonable price. You can buy something prettier later once you're sure you like shaving with a straight.