VIVA LA RESOLUTION!

Well things are going well for my first animation. I love this software and have gotten past a few kinks in the road. I’ve been looking into what resolution would be best. Now I don’t know enough to make a custom one and don’t feel comfortable doing this. The one I WANT to work in, is of course HDTV. But even for a 5 sec camera pan scene, it’s a large file. Now that SHOULDNT be a problem, because I think Youtube lets you upload large files…I think. And even if I do it in HD, then everyone should still be able to watch the animation correct?
I was also thinking of doing it in HD, because when it comes time to look for (any suggestions are welcomed!) for software to combine scenes, I fear I may lose some quality and it would be better to lose it from HD instead of…let’s say PAL or whatever it is. I also fear the software is going to make the file smaller, which isn’t a bad thing but it would hinder the quality correct?
There is not one specific question here. Just curious about it all.

http://www.toonboom.com/support/forums/animate/index.php?board=16;action=display;threadid=3224;start=msg15354#msg15354

http://www.toonboom.com/support/forums/animate/index.php?board=15;action=display;threadid=2732;start=msg12922#msg12922