I ran across this article on one of the blogs I frequent. This study tracked specific cell phone models for a year. The results are, well, let's just say I'm glad I didn't get a Blackberry. 

To Your Sucess, 

 Tim

Research group SquareTrade recently released the results of a massive cellphone study. They tracked 15,000 individual handsets over their first year of use, and they found some large discrepancies in reliability. The iPhone malfunction rate sat at a comfortable 5.6%. The Blackberry (in its various incarnations) jumped to 11.9%. But it's all better than the Palm Treo, which malfunctioned 16.2% of the time within the first year.
To be honest, none of these numbers are particularly good, and I have a feeling that there may be a confounding iPhone White Glove Effect—I keep that phone's glass screen in mind every time I put it in the pocket opposite my keys. (Ironically, iPhone users were found 3% more likely to accidentally damage their phones than their Blackberry/Palm counterparts.)
When projected to two years, the iPhone's failure rate jumps to 11% while Blackberries level to 14% and Treos reach a scary 21%. I guess it's a good thing we have those ridiculously binding contracts to bail us out after all. [SquareTrade via CNET]