DSLRs are really not good for shooting video. They suffer significantly from the "rolling shutter" effect -- aka "jello-vision". The video is easily distorted. DSLR video does look nice, because of the high-end lenses (glass) available, and depth of field. However, you have to shoot from a tripod at all times. Even then, jello-vision can kick in. Still photographer SLRs simply do not make for good video cameras right now. (The one example would be the almost-vaporware RED Scarlet-X. But you'd have to mortgage a house to afford it PLUS it's on backorder for an unknown amount of time!)
NTSC and PAL is simply a matter of frame rates now, in HD land. Resolutions are the same. A lot of cameras shoot 24p (1080p24, 720p24), so you'll be shooting in film framerates that can semi-easily be converted to PAL or NTSC distribution formats. And then Blu-ray supports most standard framerates, including film.
HDV is like an HD version of your current DV camera ... sort of. It's doubled from 720x to 1440x along the horizontal axis for Full HD (1920x1080) -- but it instead of 1920, it's sampled from 1440>1920 later on in an editor. It's not "true" HD, but it's close enough. The vertical resolution is true HD. SD DV was x480 or x576, while HD DV (HDV) is x1080. Regular 720p HDV is a normal spec of 1280x720. HDV is pretty much a dead format now.
AVCHD shoots in H.264/MPEG-4, and can be cumbersome to edit on anything other than modern high-power quad-core CPU computers with a lot of RAM (8GB or more). The video is compressed, and generally worked best converted first to some lesser-compressed or lossless intermediary format like DNxHD, ProRes422 or Cineform. I like to work with ProRes422.
The convenience and enjoyability to SD DV will largely be lost by upgrade to HD video. For this reason, even I still shoot with a Canon DV camera.
I have a Nikon D3s that shoots HD video, and it's not convenient or fun to use.
HD cameras don't really get to be both quality and easy-to-use until you start to spend a lot of money for something from Sony or Panasonic. For example, Sony's $25,000 XDCAM PMW-500. Yes, $25k. Again with the house mortgage to get a true upgrade to with the kind of quality you found on DV cameras, excluding HDV. All of the cheap "HD" camcorders out there compress the heck out of your video and then store it on highly-unreliable SD cards. But it's cheap HD for the masses.
My honest advice is to just stick with a good Canon DV camera.
HDV cameras generally are not too bad, but they tend to cost a couple of thousand dollars.
For example, the Sony HDR-FX7 3-CMOS camcorder for $2k:
http://www.amazon.com/gp/product/B00...SIN=B000IBDWNS
Maybe save a few dollars getting it used.
But it you absolutely must have a low-cost HD camera, buy the most expensive Canon branded camera you can afford.
Amazon has quite a few models (and the best prices):
http://www.amazon.com/mn/search/?_en...ch-alias%3Daps
Don't forget to buy several huge 2TB hard drives for your computer. You'll need them.
Much in the way that HDTVs made all your old videos show their true quality (i.e., look worse), HD camcorders found a way to make video shooting and editing more cumbersome. Shooting a tape and shelving it, or shooting a tape and quickly whipping out a DVD, isn't going to really happen with HD cameras.
Trust me when I say I wish this wasn't the case.
