I think we just had a thread on this, did you search? In a nutshell here is the breakdown:
HDD cameras: no removable media, so its a pain in the ass for vacations when you might not have time for downloading the video to a computer all the time. Otherwise good cameras
MiniDV: The standard format, a ton of selection from every manufacturer, the tapes are cheap and available everywhere, it is a digital format so you can get them in HD, 16:9, etc. I would recommend an HD 3 ccd camera personally, but they are $$.
Direct to DVD cameras: Cheap junk for the most part, lack features, and if you give them a good bump while recording they will glitch and screw up (true with the HDD cameras as well, rotating mass is not as tough as tape). Only hold 30 minutes at most on the expensive little DVDs. Great for grandmas that have no clue what firewire is. You have to rip the dvd (which is in some weird format) just like a normal one to do video editing, pain in the ass.
I would get a high end MiniDV camera if I was shopping today, I have a top of the line Sony from a few years ago and it works really well still.