I've been using a AVCHD flash based camera for about a year. (The Panasonic HDC-SD1). Not using tapes has been AWESOME. No dropouts, no tape storage problems, ect. Some of my tapes from 1997-2000 aren't holding up as well as I'd like. With AVCHD I just use a 4GB or 8GB SDHD card and then burn the raw files to a single or double layer DVD for storage. This cheap consumer model has a MUCH MUCH better picture then my Sony VX2100 could ever record.
Editing has gotten easier, but is still a bitch. Adobe still doesn't support AVCHD, and I still like/use Premiere 6.5 which doesn't support any HD. I use Ulead Video Studio 11.5+ to convert the AVCHD files to DV. Take the DV files into Premiere to find my in/out points and edit audio if needed. Then go back into Ulead and edit the files (bring the WAV files in if I edited audio). Ulead has a proxy file option to help edit the HD files (makes a small VCD/DV file that it uses in place of the HD file but the edits are done on the actual HD file), but I like using Premiere for my editing. It's "snappier".
AVCHD has come a LONG way. Mine records at 13Mbps, but the new ones coming out are recording in the full AVCHD standard of 24Mbps, and in 1080p. They are saying that the 24Mbps ones are HDV killers. I'm not going to argue if they are correct or not, but I do like not using tape alot. I will be replacing mine by the end of the year with one of the new ones. Either Canon or Sony.
Here's the new Canon coming out:
http://www.camcorderinfo.com/content...HG21-35382.htm
To answer your question - I wouldn't bother with a hard drive unit for 2 reasons. The cards are perfect sized for DVD backups (if I record a 10GB scene and don't have a bluray burner how do I back it up?), and the hard drive is a moving part that can break that I'd rather just not have in my camera.
Here's a sample video I shot with my SD1. It's a torrent. Feel free to seed it if you want.
http://www.amateurupskirts.com/promo...96.TPB.torrent