If your native format is DV-NTSC and you have the time, I'd upload the DV-NTSC quicktime and be done with it. YouTube limit is 10 mins or 2GB, and most videos are (or should be) 2-3 minutes, which will be well under both of those limits.
Also, I'll take this opportunity to disagree with Strypes - if your source material is SD, I'd export it at native resolution and upload it. When YouTube expands their resolution again, you'll be already grandfathered in.