Recover Bookmarks, Mail, iCal and more after HardDrive upgrade
Though not a selective copy, you could use Migration Assistant (under /Applications/Utilities) to copy your entire user data from the older hard drive to the Mac. Turn off Time Machine before doing this (to avoid unnecessary backups and slowing down the migration).

Since you already have the user account and Migration Assistant has created a second account, there is no simple way to merge the two accounts (definitely not the configuration used by various applications and the data, since there may be conflicts). But you can copy over data across from the individual folders under the home directory (and somewhat tediously, application data on an application-by-application basis).

See:
How to use Migration Assistant to transfer files from another Mac
Using Migration Assistant on Lion
Combine two+ Users Accounts on the same machine
Transferring files from one User Account to another