Conventions? choice of install directory?

[ac]

After downloading something like realplayer 10 binary (note1), into an 
initial download directory, I can run it either as user or with sudo. 
As user, I think I have to install it into a location in the home/user 
directories where user has write permissions, but with sudo presumably 
I can choose an install directory anywhere (?)

As it happens, using sudo, I chose to install 
into/home/user/realplayer  which worked fine.
However, during the installation process the sequence asked me
if I wanted system wide symbolic links (I chose this)(note2) and asked me
where it should put the symbolic links, suggesting   /usr which I 
accepted.

I am not very clear about the exact significance of these links, or 
maybe links in general, but is there a more conventional or a more 
elegant place for the installation directory, other than my present 
choice of /home/user/realplayer?

I do not really want to have an application in the user directory even 
if it is owned by root. Should I have asked for the installation 
directory to be in the /usr directory to start with?

note1:
RealPlayer10GOLD.bin

note 2:
this seems to correctly enter real player into such things as the menu 
system, which I prefer.

(I am using Kubuntu, if it makes any difference)
tia
-- 
ac