Sound dock recommendations needed

[Donald L. Roberts]

A few weeks ago, the subject of sound docks for IOS devices was 	 
discussed to some extent.  I want to make sure that my understanding of 
the type of system under discussion is correct.  I understand sound dock 
to mean an amplifier/speaker system which contains some sort of platform 
with a 30-pin connector for iPhones 3GS, 4 or 4S.  If we are on the same 
page, I would like recommendations for good quality systems which can 
function on AC power.  If it also functions on batteries, this too is 
fine.  I need the kind with the 30-pin connector because I know that 
there are some real bargains out there, and also because I want to play 
my 4 and 4S through such a device.  Please tell me the good and bad 
points of any such device with which you are familiar.  I would 
especially appreciate brand and model numbers if you know them.

Thanks for feedback.
Don Roberts