Description of problem:
/etc/inputrc currently has the following default:
"\e[5~": beginning-of-history
"\e[6~": end-of-history
This maps beginning of bash history and end of bash history to the keys pageup, pagedown. 

I'd suggest to replace these with:
"\e[5~": history-search-backward
"\e[6~": history-search-forward
This maps history auto completion to pageup, pagedown keys. So what this does is, if you type the first few letters of an already typed commandline and press pageup (pagedown) the already started line will be auto completed with what is found in your bash history.

Reason for doing so:
Bash history has a backlog of 1000 commands, does somebody really wants to go all the way back 1000 commands and use the again frequently? Not so sure...
Instead make good use of these keys by using history completion.

Example:
# ls /etc/inputrc -alh
-rw-r--r--. 1 root root 801 2009-04-10 10:42 /etc/inputrc
... (lots of other command)
# ls /et<pageup>
will complete to
# ls /etc/inputrc -alh