Lion here. I only had the error once where I had to restore. But I'm regularly having to plug in now, cause even if I initiate the sync from my iPhone, my Mac will tell me the iPhone isn't attached.
Yeah today is the first time iTunes has come back and told me I have a new phone and asks if I want to use it as new or not. I just canceled. It also gave me the error last night that the iPhone wasn't connected when I tried to sync. The only difference I saw was that I enabled wi-fi sync a couple of days ago and last night was the first time I had tried to sync via wi-fi. Wired also gives me the same thing. I also went into Xcode and deleted all the crash logs from my phone too. Those are the only changes I've made.
Interestingly enough, I noticed iTunes tried to re-download a song from Linkin Park that I gotten awhile ago and came back with a corrupted download error. I also use Lion and there is no current known way to uninstall iTunes in it, which makes things worse.
I logged into my dev account and noticed that my team provisioning profile certificate is invalid, but when I check the details it says it's managed by Xcode, so I am not going to worry about it until my phone is affected by it.
Hopefully there are no updates to a few games I have until the after the next betas are released. It sucks finishing them and then can't sync them since there's an issue. Some of them take a lot of work...lol