best way to combine multiple hds to one

so i've got multiple hds
250g
500g
1tb

all filled with music
and a bunch of the same albums on the hds
what is the easiest way to combine them to my new 1.5tb
i know i can do them one album at a time but it would take me days
any help appreciated

anyone used any programs to eliminate duplicates?

in itunes, click files and then show duplicates. Eliminate any one you like...

iTunes actually has this feature built in. It should be under:
File -> Show Duplicates, but may be in a different place depending on the version of iTunes you have.

appreciate the itunes answers but was more trying to figure out the best way to consolidate the files onto one hd
opening up each artist one by one and adding the albums will take forever