I am now at about 27,000 miles with no issues. Continuing maintenance (oil changes, tire rotations, 15,000 mile service,etc.). Still no complaints, still love the vehicle. Averaging 22 - 23 mpg, which for an SUV is pretty good. Still recommending the vehicle.
Update - January 2009.
After a few trips to the shop (airbag light kept coming on for the drivers side), they finally replaced a bunch of sensors and such to get it back to working normally. They tried resetting it a few times, but that only 'fixed' the issue for a few weeks and then the light came back on.
Personally, I don't think this is so much a problem with the car as it was with the dealership that I have been working with. I moved in July of 2008, and the nearest dealership is not very competent. I may have to drive further and hope for more competency.
I am still quite pleased with my Tucson. No other issues - still getting good mileage, and it still drives great. Going on 4 years of driving this car now, and I really have no complaints. Now if they can make an electric model or hybrid, it would most certainly be my next vehicle choice - and while I do enjoy the Tucson, I think our next new vehicle will be one that is more environmentally friendly.
Update July 2010:
The car is still running great. No issues and still very pleased with it. I'm averaging around 22 - 25 mpg these days, and am happy with that. Our next car will be one that is more fuel efficient, but for a 5 year old SUV, I'm certainly not complaining. It's got a little over 60K miles on it, and is due for a few of the more in-depth services, which we'll probably take care of later this year. I still recommend the vehicle, and anticipate keeping it at least another 5 years.
New update - September 2011.
Still very pleased with the Tucson. We're at around 75K miles now and still going strong. Had the 60K mile service done at the beginning of the year ($1000 or so) and everything went very smooth. Also replaced tires again with Coopers this time. Have really not had any mechanical issues to speak of. Still acceptable mileage in the 22-25mpg range (depending on how much highway driving I do), and I'm still very happy with our choice. We're debating a new vehicle as our much older Neon is finally tiring out - a new Tucson is at the top of our list!
Update - September 2012.
Another update to my 2005 Tucson. Still very pleased with this vehicle. I am up to about 85,000 miles on it, and have still not had any issues with the car. Still averaging 22-24 MPG, and continuing with regular maintenance (oil changes, etc). I had an alignment done after a very rough driving vacation last November. But in general, this car has taken everything I've dished out (and let's just say I've put it through more than I probably should have), and has never complained once. We've definitely overloaded it a few times with regards to weight, and I'm pleased to say it's held up to everything.
We're looking to potentially replace a 2000 Dodge Neon with a newer vehicle, and a Tucson is definitely on the list!