Downloaded Mac OS X 10.4.11 - Now what?

I finally was able to download the upgrade for my Mac in order for my iLife to work. I was able to get my ISP to give me unlimited time before disconnecting me from the internet, so my dial-up had time. Now I have it on my desktop and opened it to install it. I got as far as Select a Destination. It gives me only the choice of the Macintosh HD 148GB (134GB Free). The update requires 205MB of space. What can I safely discard to make enough room for this update?
I do not use Garage Band, I don't have an ipod, I don't use Quicken, Appleworks or Instant Messaging. Basically, I want to control my web site, and I use my computer to contact and be contacted by prospective buyers. The bells and whistles don't mean much to me, but since everything seems to be related I am not sure what I may discard.