There are a lot of people who will give you better advice than this...
BUT...

be clear -

WIDESCREEN is a format - it's the ratio of height to width - it comes to us from the old Cinerama film days (and Todd A-O, etc) - the generally accepted TV widescreen format is 16:9 vs. standard television formatting of 4:3 - Hollywood came up with this unweildy format as a battlefront to get the new TV viewers out of the living room and back into the theaters. In the hands of a master like David Lean (Far From the Madding Crowd, Dr. Zhivago) - on a huge screen - it was breathtaking. On a 17" tv - it sucked.

HI DEF is a resolution - you can have a HI DEF pictue formatted to 4:3 (or any format, for that matter, including vertical - but the general HI DEF format is 16:9, as well. The huge advantage of HiDef is that extreme sharpness and clarity - wow - like the difference of shooting stills in 35mm vs. 4x5 inches. Your image is 4x the area of standard def, and in the correct viewing situation, you can see it, and it takes your breath away.

Let's face it, a major force behind widescreen tv comes from the various manufacturers - it's a great way to get EVERYONE to buy a new TV set. Coupled with HiDef and 50" screens, it makes Perfect Sense!

I've personally disliked widescreen shooting for more than twenty years - it's tough to get a good close-up of a human head (which is basically a vertical rectangle or (with some people) a square, into a wide screen format without wasting (and/or having to fill) VAST amounts of screen real estate.

You rarely have seen a painted portrait of a head in a widescreen format. Most artists have traditionally used a 4:3 Vertical. You advenurers - start thinking about different screen formats - we do it all the time on the Web - so why not in video?????

Hope this helps,
v