I was wondering which patch is recommened over the over. I am trying to learn how to secure the kernel, and I, of course, would like to learn the security patch that is the best.

currently i have a 2.4 and 2.6 kernel (i have two machines).

thanks in advance!
:-)

RSBAC:
http://www.rsbac.de/

but for a newbie grsecurity is easier to learn

is grsecurity as good as the others??

It is easier to configure and it does pretty good job for workstation.
Remember that aplying patches does nothing, you need to know how to configure SELinux or RSBAC.
Few examples:
atfer aplying RSBAC and rebooting you will not be able to login for the first time (or at all if you don't know how to enable soft mode), you need to know what to do, where you passwords will go, your /var/log/message will grow to ~500MB in the first few hours if you don't know how to manage it, and so on.

So start with easy (and really good) grsecurity. Still you may not be able to start X or X may freeze randomly, if you don't know how to configure it. So don't worry there is enough to learn from grsecurity.