Meh... Somewhere between decent and failure lies NASCAR 06.
The game itself is pretty good, bringing all 22 NASCAR Nextel Cup Series tracks, a few Busch Series tracks, and some fantasy ones. Include a major portion of the Nextel Cup superstars, (there are a few glaring omissions though) and the new team control system and you have a pretty good game on your hands.
But the downsides... Fight To The Top is back again this year, and while it is a little bit better, EA needs to make it a true Outhouse to Penthouse story by bringing back a few of the features from Thunder 2004, such as having to build your own equipment and team from the ground up. A plus for the Career mode in the game is the fact that you can adjust your race length settings in this one, so you can get in a quick race in career instead of doing a painfully long one when you don't have time to. The car sounds are excellent and the best in the series, but after playing GT4, it just wasn't enough to really get me going. The music, aside from the main themes "Thunder" and "Go Faster", is boring and repetitive. Thank God for my headphones.
In closing, TTC:06 is an okay NASCAR game, but it tries too hard and ends up messing itself up.