I would not recommend mixing HD and standard video footage in Premiere Elements. It's best to convert if necessary to ensure that all of the video
going into a specific project is of the same format.
It's less of an issue mixing widescreen and 4;3 -- except that your video will go from 16:9 to 4:3, which can be a little distracting to watch.
As for whether HD will give you a better web video than standard DV -- well, this is web video, so it really won't make that much difference since video for the web is more like 320x240 or at mox 640x480 rather than 1900x1080.
Same for DVD. DVD is standard definition. That means no matter what you put into it, if it comes out a DVD it comes out standard def video.
As for quality video, you can get great near-broadcast quality with a Canon HV series camcorder that records HDV. Even if you rez it down to standard DV, your picture will be rich and clean. Assuming you've got good lighting, etc.
Thanks for taking the time to help out a newbie with some useful information. Much appreciated. I also found another post relating to the mixing of formats, which made things a little clearer too!
I'll look into these cameras. Is the output format i.e. PAL or NTSC of a camera determined by which region it is sold in?
PS - with regards to light. We live in a place where the sun shines virtually 365 days per year and we are surrounded by crystal clear sea water and mountains. So in terms of natural light for filming and some good subject matter, I hope it will be productive.
You should get excellent results with that lighting, Craig!
And, yes, I would expect your camcorder to produce video in the format (PAL or NTSC) in use in your area of the world!