Enightening sought: User-ID, Owner & Permission

[SYNass IT Ubuntu / Linux]

Hello Ubuntuans
I am still using my very first setup (October 2007) in a single
partition.

Currently I intensively prepare for my future setup of Ubuntu with 8.04
LTS 
with data backup, best HDD partitioning and ... all the things till to
restore 
my data finallly to continue smooth and seamless after all is done, 
hopefully successful one day. ;-)

When Ubuntu is installed one is asked for a "user name" and its "user
id" and 
normally I had set my/our respective personal ones !

All these I plan to keep, remain and use again !!

But I have following idea:
The very first user-id and user name shall be the same on all
systems !!!

Sample:
My data entered normally are: svobi & my full name !
With my future plan it thought of: sn & its full name ...
... and the previously used one will be the second one !?

Is this a good idea or woul you stop me from doing so ???

Your advice, guidance, hints, sugestions and warnings 
are hot awaited and welcome. ;-)

TIA & cheers, svobi