They have 3 short shows in HD, from what I hear and only HD cameras in 1 studio and the amount of field work they show from other sources, it will take a long time to get it all over to HD, so for now, I would rather see them add things like Sci-Fi, USA or especially Speed...
A local Kansas City News station went HD recently, they did all the studio cameras, field camera, etc and it looks nice. CNN is so big it will take mega money and time to switch.
If E had unlimited bandwidth to do it, sure, but for me it's sure not at the top until they get alot of HD content.