I meant using divx for all versions.
Use a multipass vbr on the video
ac3 on the audio(assuming you have a good source, otherwise just use vbr mp3)
I'd only use 1 codec for all, you can adjust bitrates and resolution to get the filesize were you want it for dailup users.
Most of the "HD" vids sponsor are advertising are nothing impressive, most seem to think widescreen=HD. The quality if nothing to write home about, filesize is 4 times more then it should be. Just wasted bandwidth.
Sorry, just a rant of mine
