I've seen this mentioned on some other forums, but was curious to see of anyone else here has had this problem... I recently returned a Droid because the headphone jack was going bad; it was perfectly fine when I got the phone, but after four months or so I started hearing cracking and popping and it kept getting worse.
So I went to my local Verizon store and told them the problem and asked for a replacement - as an aside, they were great about it, basically just placed an order for a replacement without any hassle whatsoever.
However, when my new phone came I found that it's even worse than the first. You so much as touch the phone (or even move it while holding it at all) and the cracking and popping is constant. It's basically useless for listening to music - which is one of the main things I'd like to use it for.
I plan on replacing this one as well while the warranty is still active, but based on what I've read on various sites, this seems to be a common problem for the Droid. One guy went through five of them (and had a sixth in the mail) due to this same problem.
It's a shame - aside from this one issue, I have been very pleased with the Droid.