can i upgrade ubuntu 32 bit to 64 bit without losing my files?

Yes, download the 64Bit version of Ubuntu 8.10 and install WITHOUT format the /
it will maintain untouched your /home, with all files, and configurations.
You have to reinstall the programs.

by the way 64bit can be a little more advanced, by default, all software is on 32bit today.

I'm on a 64bit machine and find 32bit does all the multi-threading and everything else that i'd expect from a 64bit version. 32bit is limited to using 2Gb Ram (it just ignores the rest) but hardly ever needs even 1Gb of it.

I was happy with the 64bit version but 32bit actually seems a lot better for me. If you have a comfortably spare 10Gb on your hard-drive then it'd be great to setup a dual-boot between 32bit and 64bit to compare the differences. 32bit has the advantage of being used more and had a lot of bug-fixes and tweaks. Also as Jaun says there's a lot more in the repositories for 32bit. For me the main issue was that Wine is still only really 32bit so i found some trouble running Windows stuff but now i'm on32bit i don't use Windows stuff at all! lol, a classic.

As Jaun also said you can avoid formatting your partitions while installing but its easy to make a slight error so backing up "/home" is a good plan. When you get to the Partitioning section of the install i tend to go for "Manual" partitioning and make sure there's an UNticked box for "Format Partition?" for every single partition. Ideally it's good to put your /home folder on a separate partition so that you can keep changing your OS on its partition without worrying much.

Good luck and regards from
Tom :)

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Good luck and many regards from
Tom :)

I had been wondering the same thing, I just discovered the small, tiny tab on the "download Ubuntu" page that gave the 64-bit installation option. Had I seen this before: I would have installed the 64-bit edition. I have over 4gigs of ram on my machine, and i'd like to utilize the full strength of my box.. Still, I love the 32 bit edition but am very much so considering upgrading...

On a side-note: You mentioned it has bugs... This is very unappealing. is it unstable? I'll stick with the 32-bit edition I guess.... :-(