...how do I keep my droid and the files on it secure??
Two things that I've done to enhance the security of my Droid (not an Eris, sorry) are as follows:
1) Create an "unlock pattern" so you have to enter a specific pattern on the unlock screen to unlock the phone, rather than simply sliding the unlock button from left to right. Sure, it means you've got several "swipes" to unlock the phone, but at least no one else can do it when you're not looking (or if they steal the phone.) But, like I said, I'm running a Moto Droid, not an Eris, so maybe the Eris doesn't have the "unlock pattern" option on it? I can't help you there, but maybe an Eris user here can...
2) Download and install WaveSecure Beta from the Marketplace. Right now it's free, because it's in Beta-testing, but in the future it will cost money (a subscription of about $20 per year). This allows you to remotely lock and/or wipe your phone using their (wavesecure.com) website. I've tested the lock-feature on my Moto Droid, and it did work, albeit a bit slowly. (Like I said, it's still in beta... So it will get better, I'm sure). Even though it's in Beta, it's still better than nothing.
About your other questions you had, I'm really not sure how to eliminate the duplicate entries you're talking about... I simply chose to sync Facebook with contacts that are already in my list, rather than having Facebook add contacts to my list... And I don't use Windows Live or Outlook... So my Google Contacts are all I've got. I do that deliberately so I won't have the duplicate-problem you're having. Hopefully someone will post an answer to your question, and we'll both learn something.
Best of luck!
