I just bought an HD video camera and I did quite a bit of research. Picture quality wise the Panasonic HDC-TM700 seems to be the winner. However, there are a couple of drawbacks that kept me from buying this camera. The first one is that it has an on-board fan which can be heard in the audio during playback. If you're going to only edit your movies and play music over them then it's probably not that big of an issue. But if you're filming your kids school play you probably don't want to hear a fan in the background. The second issue was that it records 60 frames per second. While that's great for picture quality, if you're going to do any editing you're going to need a mother of a processor on your computer to handle that kind of load. The camera I bought is 1080i / 30 frames and my year old dual core computer still struggles during playback.
While I would love the picture quality of the Panny, I'm on a budget and don't have the cash to upgrade my computer, as well as add an external mic. Instead I opted for last year's top of the line Sony model that I got a great deal on. I was leaning heavily towards the Canon HF-S20 that came out this year, but it was a grand. I got the Sony CX500V for $750. The Canon probably has a little better picture for outdoor shooting, but the Sony does almost as good and has better low light and stability control. For the difference in price between the two I was able to buy a stand alone DVD burner that will burn high definition AVCHD DVDs that will play in my Blu-Ray player. I am backing up my AVCHD files on external hard drives for down the road when I get around to upgrading my computer to one that can handle playback and editing.
I am VERY happy with the Sony. It will keep me happy for the next few years until it becomes a dinosaur and I have to update everything again. :(