I recently traded in my Mercury Cougar for an Audi A4 3.0 Quattro, because I wanted a more reliable car that handled well in bad weather. So far, it seems that I've chosen well.
While I was comparison-shopping, I also test drove the BMW 325xi and the Jaguar X-Type. They were nice cars, but they couldn't offer the level of options and power that the Audi A4 had for this price. The Audi also seemed to be built better, with near-perfect fit and finish on every part of the car.
Of course, to truly appreciate the A4, you need to take it for a test drive. When you do, you'll find that the car corners well, accelerates quickly, and has good traction. The Quattro AWD system also does an nice job in bad weather, and gives you a feeling of control no matter how slick the pavement gets. My car also came with the 5 speed triptronic automatic, which is fun to play with when you want to shift the gears yourself. I'm not sure how useful it really is, however, because the car seems to accelerate faster if I just leave the shifter in automatic "sport mode". This car is rated to do 0-60 in 7.2 seconds, which seems about right in my experience.
While you're out on that test drive, I'd recommend checking out all the options. Audi really loaded this car, which is one of the main reasons that sold me on the A4. The stereo is particularly impressive, which comes standard with a six disk CD changer, and a ten speaker sound system with a subwoofer. It sounds good, and is very easy to use with the steering wheel controls and trip computer integration. You can get also get Bose speakers for another $700, but the stock system sounded good enough that I really didn't think it was necessary. The premium package also includes comes with some slick features like a compass and auto-leveling Xenon headlights, which BMW and Jaguar charge extra for. Audi also included some really thoughtful add-ons like a standard first aid kit and an extra sun-visor in the center of the dashboard, which most other car lines do not seem to offer.
My car also came with the cold weather package. I initially didn't want these features, but I ended up being glad that I got them this winter. Leather seats seem to get VERY cold when I leave the car outside, and the heated seats make driving the car MUCH more comfortable when it gets below 20.
The only problems that I have with the car are some minor ergonomic issues. The drivers seating area is narrow, and I found that I occasionally bump my knee against the center console when I take a turn. Also, even though Audi put 12-way power seats in this car, I still can't seem to adjust lumbar support to exactly how I like it. These problems are really minor, however, and do little to detract from what is otherwise decent car.
UPDATE: Now that the car is broken in, I can accurately report on the gas mileage. I've been getting an average of 17 city and 23 highway, which is slightly less than the EPA specs of 18/25. Of course, you don't buy a car like this for great fuel mileage, but filling the 16 gallon tank with premium gas every week gets expensive.
UPDATE 2: I've recently dropped my rating on this car due to Audi's poor customer service. It is downright painful to get assistance with things like vehicle registration transfers and reporting of safety defects. Expect to be put on hold, transferred to various departments, and wait for weeks to get the required paperwork. Scheduled service also costs a fortune once the warranty expires. Expect to spend at least $300 a visit for each annual/10,000 mile service, and well over $1,000 to have the timing belt changed at 80,000 miles.
Amount Paid (US$): 37500
Condition: New
Model Year: 2003
Model and Options: 3.0 Quattro with cold weather and premium packages