entering HD world: doubts

FCP 6.05, MacBook Pro 2.2 GHZ Dual Core 2 - 2GB RAM, Leopard up-to-date

I am looking for someone to read my issues/doubts and help throw ideas back and forth so I can make a good decision about buying equipment.

OK, so I am a latecomer, intending on stepping into HD world. I am looking for advice on the pros and cons of a few options out there. As a reference, I am a filmmaker who likes to work with prosumer equipment, small cameras with the basic manual features / imputs but good image quality. My last camera was a Canon Optura Pi which did 30p (simulated) and I was quite happy with it.

1- So, I see there are these new cameras that record onto SD cards and internal HDs, in "Full HD" (1920x1280) format MPEG4-AVC / H.264. These recorded in a format that has to be converted in order to edit in FCP6, correct? How much image quality / resolution is lost in this process, and is this conversion a long process? My Mac's specs are above this message.

The audio format on these is surprisingly below the usual miniDV 48 Khz 16 bit quality... it seems to be AC3 Dolby-type format, which is compressed, correct? Kind of like Mp3? How much of a difference is this in terms of sound quality?

What sort of backup process are people doing for these cameras that don't use tape? Since there is no more tape to store away and recapture when needed, how are people dealing with long-term storage? Just plain large hard drives?

2- I am looking also at some HDV cameras, especially the new Canon Vixia HV40, which CLAIMS it records in full 1920x1080 onto HDV tapes... But isn't the HDV format essenctially 1440x960 in reality?

How does the image quality of cameras like this one compare to the new AVC format cameras, at least in terms of codec, compression quality... I know that other factors are involved, such as sensor size, lens quality, etc...

The attractive part of these cameras is that they will play my old miniDV tapes. But on the other hand, sticking with the soon-to-be-obsolete tape-world means I will need to get a HDV deck/player so I don't wear down my camera by using it as a player when capturing, correct?