I want to move to FC6 from FC5 . The release notes suggest that a fresh install is better . Can I just copy the Home Directory and copy it back after Installation . Maybe using Rsync ? Or is Dump better . Will Restore , restore the home directory after FC6 installation .
How much time would an upgrade take with my not new hardware. Is it worthwhile to move to FC6 with this hardware?

I believe the answer to all the methods you list in your post is "yes", although if your rsync is an initial rsync where everything is backed up, you might do better with backup or tar.

Be sure you back up "/home" no matter what method you choose. To be really safe, I like to make two backups to different media just in case you get a media read error on one of them when trying to restore. If you can trim the size of "/home" to fit on a cdrom, that might be a good choice too.

Another possibility -- if "/home" is in its own partition, you should be able to install fc6 without touching "/home". Of course, you should back it up anyway just to be safe. (In fact, now would be a good time to take a full backup of the entire fc5 system.)

The time it takes to backup or backup/restore depends on your hardware so I don't even have a guess on that.

Thank you so much .
There is one more confusion I have.. This is that a lot of programs create their directories in the users home directories . Will the settings there conflict with newer versions of the programs? In case they do will the new version of the programs automatically make corrections.
I am particularly interested in retaining Scribus a DTP package.
Incidentally there is another way of Backup which I found here in Linuxquestions . That is DD. There is a document which I downloaded called "How to do everything with DD". It may not come up in a search as "everything" is spelt as "evevything". I am not inexperienced do you think I should use the options given there ?
I have not tried it out yet for backup as it appears to be quite dangerous to use.

One more thing ... I am already using the latest Kernel . What is the difference between FC6 and Fc5 . I suppose only those who are on the project can actually answer this. I have read through the release notes and can see many differences.

Why don't you wait for FC7 since it will be out late May and to be honest, I don't really see a lot of need to change (I run both).

That said, I did an upgrade that worked fine - you could do the backup as suggested and try an upgrade, and if that doesn't work, go fresh

Why do I need to upgrade ? .
But I will take all precautions .
So at the least problem I will restore FC5 . Two of the tricky things I am not sure of is setting up HPLIP correctly to get my PSC1315 working fine . Then I am also using Logical Volume Management . But I want to start with a clean slate and let Fedora assign the partitions etc.
. By May I will ask questions about FC7.