There are really only two primary choices: four-door sedan or wagon. From there, it's a matter of choosing the engine, and whether or not you want all-wheel-drive.

Understanding Mercedes' alpha-numeric nomenclature helps, and it's actually not that difficult. The letter or letters at the start designate the car: C for the compact C-Class sedan, E for the mid-size, S for the big luxury sedan. The numbers after the letter designate the engine size, if you imagine a decimal point after the first number. E320, for example, means an E-Class car with a 3.2-liter engine. E500 models come with the more powerful 5.0-liter engine. Somewhat of an exception to this is the super high-performance AMG cars, which get only two numbers. But the process is the same: The E55 AMG has a 5.5-liter engine.

The E320 ($49,220), powered by a 221-horsepower V6, is the least expensive and most popular E-Class. It comes with the standard equipment buyers expect in this class, starting with fully automatic dual-zone climate control, a power tilt and telescoping steering wheel, 10-way power front seats with leather seating surfaces, real burl walnut trim, a nine-speaker stereo, power windows with one-touch express operation up and down, auto-dimming mirrors and rain-sensing windshield wipers. Popular performance options include 4Matic full-time variable all-wheel drive ($2,500) and a Sport Package that includes high-performance tires and the Airmatic computer-controlled air suspension.

New for 2005, the E320 CDI ($49,795) is equipped identically to the E320. The distinction is the impressive CDI turbodiesel engine. If you haven't driven this sedan, you don't know about the latest in diesel-powered cars. However, due to late changes in emissions mandates, the CDI is not offered for sale in California or the Northeast. For now, the E320 CDI is a 45-state car.

The E500 ($57,620) has been gaining sales ground on the E320 in recent years. Powered by a 302-horsepower V8, the E500 comes more standard equipment than the E320, including a seven-speed automatic transmission, a four-zone climate control system with separate temperature adjustments for both sides of the cabin, front and rear, and the variable ADC air suspension.

Nearly all the upgraded equipment on the E500 is available as options on the E320, and there are dozens more options offered on all E-Class models, including the high-tech stuff people expect in luxury cars. The extras include radar-controlled Distronic adaptive cruise control, which maintains a set distance from cars ahead; Keyless Go, a credit card-sized transmitter which allows unlocking the doors and starting the car by touching the door handle and the gear selector; Parktronic obstacle warning, which helps with parking and enhances safety by alerting the driver to objects in front of and behind the car. Also available: DVD-based GPS navigation integrated in the in-dash information management system; voice operation for the phone, audio controls and navigation system; ventilated massaging seats; and solar-powered interior ventilation for those hot summer days when the car is parked for long periods. There's even a power trunk closer.

The E320 wagon ($51,470) and E500 4matic wagon ($61,220) are equipped comparably to the respective sedans. The 4Matic all-wheel-drive system, optional on the E500 sedan, comes standard on all E500 wagons; the system is also available for the E320 wagon. And while there may still be social baggage associated with station wagons, anyone put off by that image is losing out. The E-Class wagons give up almost nothing to the sedans in performance, fuel economy or handling dynamics. They simply add an element of versatility the sedans can't match, and they are quite handsome to boot. A power liftgate and cargo organizer are standard, and the E-Class wagons add something rare among their European counterparts: a folding third seat that increases passenger capacity by two. Useful equipment such as a slide-out load floor, roof racks, bike racks, ski racks and cargo boxes abound on the wagon option list.

The E55 AMG ($80,220) is performance-tuned by Mercedes subsidiary AMG. It's equipped with a supercharged, intercooled V8 producing 469 horsepower, a manually controllable 5-speed automatic transmission, bigger tires, wheels and brakes and an aggressively tuned ADC suspension. This hotrod is distinguished by a unique body package, interior trim and AMG markings inside and out.

No new Mercedes would be complete without safety advances. Every E-Class cars come standard with eight airbags: dual front airbags, side-impact bags both for front and rear, and head-protection curtains that run the length of the cabin on both sides. The airbag management system employs multiple impact sensors designed to more precisely control the timing and rate of deployment. The system accounts for the weight of a front-seat passenger and controls seatbelt pretensioners according to the force of impact.