I actually got into road biking through riding fixed, and the fixie is still my primary commuter. I built it up as sort of a junker so it'd be less likely to get jacked, but it's still tight and fast and to date I've spent less than $200 on it (including $50 donor bike off craigslist).

Couldn't say whether it's helped my road riding since the fixie came first, but for a total newcomer I sure seem to be leaving a lot of guys behind.