MP3 files to Apple lossless

This is for the digital guys. I have most of my digital files in itunes ripped at 320 and 280 kps. I noticed that there's an option to convert files already ripped to "Apple Losseless." If the files are already ripped at 320, 280 or 190kps is there any advantage converting them to apple lossless, or I is better to redo the whole process and start ripping them from your original CDs.

Thanks in advance,
As you seem to suspect, there's no advantage to converting them to Apple Lossless. The data that was lost when the files were ripped to mp3 can't be recovered. You'll have files that take up much more space but sound the same.
However, before you start all over, it would be worth re-ripping a couple of CD's and seeing if the difference between lossless files and the mp3's, especially those at 320 kbps, is worth the trouble.
Sfar, appreciate the quick response.
You make a good point if the difference is worth it. I have more than 11,000 songs, and it will be painful for me to start all over.
It's probably easier to sort out if you think about only those CDs you really listen to a lot and that you know are well recorded. Do a few of those and don't worry too much about the whole 11,000 tunes for now.
Re-Rip!!! If you care about sound, Re-Rip. Sometimes when you AB a MP3 vs a lossless file the differences can seem minimal, but there is something about MP3s that kills the desire to listen. Hard to describe but definitely not my imagination.
I agree with Ejlif- re-rip. MP3s always sound clunky and mechanical. I can tell from the next room.
I can understand your hesitation to re-rip but having just finished ripping 2600 CD's to FLAC I am finally happy. With drive space so cheap I think it's worth going to lossless now more than ever. Once your collection is in a lossless format you can pretty much convert to any future format without loosing any audio information. I haven’t pulled a CD out in weeks.

I was originally at all 320kbps MP3 and was pretty happy but I have to admit some of the stuff is considerable better ripped to FLAC.

I would re-rip the entire collection and be done with it ... I also put together an Excel spreadsheet while I was ripping to inventory all my CDs. It seemed at first like a long and daunting task but it was kinda fun. I pulled out stuff I hadn’t heard in a while and drank a few beers while listening to music and swapping CD’s. It was kind of a “Friday Night” activity for a while. One thing to watch is errors on the disc. I am now using DB Poweramp which is really good with error recovery. I noticed the first time I ripped to MP3 – even though the program said the disc ripped fine … I had a few errors. I’m not sure what Apple has for ripping programs but I would dig deep in the settings and see if there is a “secure mode” while ripping the CDs. It generally takes longer to rip but you don’t want to have to go back and do it twice. Lastly – Spend the $100/200 and get a second (or third and fourth) USB/Firewire external drive for backup. I have 2 Terabytes of drive space that sit unplugged on a shelf, with the whole collection backed up just in case.
As per Sfar I will start re-ripping the ones that I like the most, and then eventually as horseface did, little by little re-rip my whole CD collection.
Good advice guys. Thanks a lot.