Go Big: One World (www.oneworldalliance.com), Star Alliance (www.star-alliance.com), and The Great Escapade (www.thegreatescapade.com) are airline consortiums that specialize in around-the-world packages. Most tickets are good for a year, allow on average 12 to 15 stops, favor travel in one direction, and cost between $2,900 and $3,600.
Upside: Change-on-the-fly flexibility and an armful of frequent-flier miles when you're through.
Downside: The high cost; mileage restrictions can limit your route.

Go Custom: If you can't be bothered with restrictions, consider Airtreks (www.airtreks.com) or Air Brokers (www.airbrokers.com), ticket consolidators that will customize the route of your choice. Prices usually start at $1,200.
Upside: You can tailor your route to be more cost effective.
Downside: The cheapest seats are less easily changed en route.

Go Off the Grid: Make up your itinerary as you go, combining bus, rail, and boat travel with cheap one-way air tickets purchased from local travel agents along the way. For the cheapest fares, look for agencies specializing in your destination (e.g., Taj Mahal Tours or Athens Travel).
Upside: Total freedom.
Downside: Unpredictable costs, availability, and, of course, reliability.

From the print edition, April 2004