I would try the following:
Export out at 2560x1440 (twice the resolution of 1280x720)
30 fps (I know everyone says anything over 24 is overkill, but I get better results at 30 YMMV)
antialias on
png image sequence. (no compression and relatively small file sizes)
Open the image sequence in Quicktime 7 Pro and export out at high quality, H.264, 30fps, 1280x720HD.
Exporting at twice the resolution and using Quicktime to scale it down will give you much crisper linework. If you are using a style without edges, then you can probably get by with just 1280x720.
I would use a scratch disk as we are talking 10's of gig of raw images. MAKE SURE you save the images into a new folder (I call mine source images) or you will end up with thousands of images in a folder or the desktop (yikes!)
Also, try to minimize big camera moves with lots of side to side head movement as this will cause jaggies. Nice, smooth choreography with gentle pans will give you smoother and cleaner final output.