I draw in a traditional page format, for various reasons. Firstly, because that's how I've always read comics. I grew up with print-comics, so I got used to thinking in that format - and secondly, it makes it SO much easier to format for print when I make stuff for cons.
I draw at 3307x4677 pixels, at either 300 or 400 dpi.
As for reading though.... I read all sorts of formats here on Tapastic! There's lots of fun stuff you can do with longer formats that work really well as webcomics, but which don't work as well in print. However, I don't like it when episodes get too long - if I have to scroll for too long to get to the end, I lose track of what happened at the beginning.