I've been going throught the selfsame torment for the last five weeks. For me the most important thing, after its being HD, was that it should be very light and small, or I just know I'd never tote it about with me enough to justify having bought it.
I also wanted a viewfinder, for reasons that, if you have read this forum over the last few weeks you'll know already.
Light, small, viewfinder and HD gave me just one choice: Canon HV10. So, that's what I bought. Plus it was cheap so that was a bonus.
Others on the shortlist:
HDR-SR7: just too big (for me)
HDR-CX6: no viewfinder but otherwise my second choice
HDC-SD1: bigger than HDR-CX6 with no other benefit
HV20: great but just too big
The fly in my ointment is the Panasonic HDC-SD7 which is just what I wanted but only NTSC, no viewfinder and records in AVCHD. There, talked myself out of that one.
There are rumours that the new Canon HG10 has overcome the AVCHD shortcomings but I doubt if it is true.
My bottom line was that if you have no tape you have no permanent archive, and you'll have multiple copies of mpeg-2 files on every PC you own just in case a HDD crashes and you lose all of your memories, whereas I'll bet you have loads of ancient VHS tapes from your last VCR gathering dust, taking no harm and ready at a moment's notice to spring to life once more. That was the clincher for me - a permanent archive from which I can always make a DVD or file copy should one get lost or damaged.
Oh, and the HV10 has far far better image quality than any AVCHD cam I looked at (IMHO).