What the best format for overlaying video

[BeFunk]

I am making a few new elements like intros and what not and looking at exporting/saving off to a video format for later use.

Any input on what the best format to use that supports alpha channel for overlaying

I.E. intros or lower 3rds

[serge26117]

Canopus Losless or Canopus HQ (fine)

[Jerry]

Here is the catch with alpha. If you are making it in a project you will be able to use the alpha. If you export to save as an avi, you will loose the alpha...unless you do the alpha matte work around.
If I need something like this I make it in AE and export to HQ with alpha. Import that into Edius and away you go. It can be used in any project then.
If you have something else other than AE, that retains alpha on export, you can create it there and import into Edius.