I've been putting this off but now I'm going to try and do the 2010.1 install from CD. I've been reading old post most of the day but need a bit more help. I've run from the Live CD a couple of times already and got everything working so that all is looking good. I know it is recommended that I do a reformat of / and /home with Ext4 so I have backed up my /home user data to my external HD.
Here is were it gets me worried :
I will check the user number associated with each user before reformating the HD. (It is like 500, 501, 502, etc.) When I do the new install, and it asks to create users, I plan to click the "Advanced" button for each one, and assign the same userid number (and name) as before. Then after finishing the install, I plan to copy the data for each user from the old backed up /home to the new /home with the hope of getting all their old Kmail settings and email, and desktop and favorites info, etc.
I think I can handle all of that but Old-Polack (I know he has forgotten more than I know)

had a recommendation as follows:
".... 2. Rename the current user directory, by adding -old to the name, then when creating your user in the new installation, be sure you have the same UID and GID as the present installation.
If you do the second, you will start with a fresh default desktop, but all your application config directories will be available, still owned by you, in the old user's directory, for easy copying.
.…You mount the partition that will be the /home partition, and rename the user directory, from the liveCD, before doing the installation, then unmount the partition and proceed with the installation. Format the / partition, don't format the /home partition.
When the installation is done, on the first boot into the installed system you have to select a root password and create a normal user. Choose the same name as you originally had on the old installation, and in the advanced section choose the same UID and GID you had in the past. The active home directory for that user will be the one newly created, but the one with the -old extension will also exist, and be owned by the newly created user too. From there you can copy the .mozilla directory to get your bookmarks and Firefox extensions back, before even opening Firefox. The same for .opera, .purple, .pan, .Skype, or any other .<directory>for any other app that has personal settings. Don't copy the .kde directory.
Copy the .<directories> one at a time, and check to see that no problems are introduced to the new desktop. If a problem occurs, after one of the .<directories> is copied over, delete that .<directory> and proceed to the next."
I think he is saying basically the same thing except he is recommending saving the user directory's (with the added -old to their name) in the new /home instead of just leaving the user directory info saved on another HD and copy it from there. I don't think it really is going to matter but I could use some clarity on how and why it really is better to do as he suggested ?