Now that I am close to settling on the Canon Vixia HV40 or the Vixia HG21, what are the hidden costs?  How much computing power should I have?  Will Adobe Premiere Elements 3 get the job done?  Do you backup your video to a hard drive?  DVD?  Will I need a special HD DVD recorder?

Any advice or cost estimates greatly appreciated.  Thanks.

You need a very powerful computer for AVCHD with at least 4 GB of RAM, although I wouldn't use less than 8 GB.  Not sure what's needed for HDV, but since it's a less spec I imagine you could get away with a dual core or even single core system.

I personally back everything up on an external RAID box.  I couldn't afford a Drobo, so I bought a similar device for $100 and I stuck four 2 TB drives in it.  Right my library of 1400ish clips plus AE projects, etc.. uses a little over 1.5 TB.  Part of that is because I keep a lot of my raw AVCHD files around for at least 6 months.

Thanks for the input.  Keep it coming.
AVCHD ... is that the format used by the HDD units?  Canon Vixia HG21, for instance??
Would the tape-based units require less computer power?

HDV is essentially an MPG2 format which is designed for fast "decoding" so that less powerful devices can playback MPG2 video.

AVCHD, on the other hand was designed for encoding.  Getting lots of data in a very small space and it takes a bit more power to decode the data, especially if you are recording at the full data rate.

I have the Canon Vixia HF11 and I record 1080p at the highest bitrate.  My previous dual-core system running 64-bit vista could not decode it realtime.  However, my current quad-core Windows 7 64-bit system can.  Although, I think that partially has to do with Windows 7 natively supporting AVCHD files now.

The HV40 is a great camera and HDV is still very good for doing stock work.  I just didn't want to deal with tapes.  Between the built-in 32GB and my 16GB card I can record 6 hours before having to unload my camera.  And I've never come close.  The most I've recorded was a concert at my daughter's school and that was 90 minutes.  You'll find when shooting stock that you tend to shoot tons of little clips.  I usually end up with about 200 to 300 small files at 45 seconds to 90 seconds average.