Converting Lossless (Wav, Apple Lossless) to MP3/AAC removes certain frequencies and bits to make the file smaller. Converting that MP3/AAC back to lossless can't bring those bits and frequencies back in.
If you have the CD's you can import those CD's again.
Thanks for the help.
On another note, to all those who want to downgrade to iTunes 8 I would suggest otherwise, because creating smartlists has gotten better in this version. You can now choose which rules the smartlist must follow and which ones are optional. In iTunes 8 you can only have it one way.
Also another small thing I noticed, now when you select numerous songs in a playlist, the # at the bottom that tells you how many songs are in the list now also tells you the # of how many you've selected, their size & their overall duration.
Little things like that are what I truly appreciate about these updates.