Moving from 10.04 to 12.04

[Jim Byrnes]

Sooner or later I will need to move to 12.04.  Before I make the move I 
need to decide a couple of things.

First should I upgrade or do a clean install.  When I went from Karmac 
to Lucid I did an upgrade.  It seemed to work well and I have had no 
problems, but I see a lot of people advocating a clean install.  Looking 
at my home directory I see it has become a jumbled mess so doing a clean 
install would give me a chance to restore some order.

Thinking about doing the clean install I came up with this idea.  I have 
a brand new spare HD.  I could put it in my case, unhook the old one and 
hookup the new one.  Install 12.04, get it running and install what I 
need.  Then hookup the old HD and copy home and what ever else I find I 
need to my laptop.  Hookup the new HD and copy over what I need from my 
laptop.  This way I have an untouched copy of 10.04 to use until I get 
12.04 setup and running the way I want it.  Does that make sense?

This time I want to try a separate /home partition. I'm trying to decide 
how much space to give / and how much to /home.  The new HD is a 1TB 
one, I will probably only format about 300GB. My current HD is 500GB and 
I formatted about 290GB and have 146GB free.

I googled trying trying to find some guidance on how to allocate the 
available space between / and /home, but found widely varying 
suggestions.   I decided to look at what I was using on my setup now

$ sudo du -shc /   =>  total 105G

$ du -shc /home    =>  total 64G

So this tells me that if I had a separate / and /home, / would be 41G. 
41GB seems large compared to sizes I saw when I doing my search and many 
of those authors said they installed "tons of stuff".  So is the method 
I used to calculate my current / size valid?

If it was valid I am thinking of a / of ~100GB and /home of ~200GB, does 
that seem OK?

Thanks,  Jim