[sdiy] Decoupling caps x3?

[Seb Francis]

Hi,

I'm noticing on quite a lot of datasheets for mixed signal devices 
(e.g.CODECs, PICs) there is recommended 3 simultaneous values of 
decoupling caps: 1uF, 0.1uF, 0.01uF.

I've always just used a combination of a few uF electrolytic here and 
there and plenty of 0.1uF multilayer ceramic (usually X7R) very near 
power pins and voltage references.

I thought 0.1uF multilayer ceramic were good enough for damping high 
frequency stuff as they have very low ESR and inductance.  Is there 
really an advantage to adding some 0.01uF caps as well?  And if so what 
type to use .. the datasheets don't specify - more ceramics, or maybe 
polyester?

Seb

P.S. This is a very good article on the general subject of mixed signal 
decoupling and grounding ...
http://www.analog.com/en/content/0,2886,760%255F788%255F97529,00.html
(but it didn't answer my question above...)