I think I use all its capabilities pretty much - although web browsing the least as I still don't like the browser that much.
I play games of course PS3 & PS2 (got 60Gb partial BC) but I also watch movies, have home movies stored on it as well as lots of pictures and music which I use as well.
One thing I haven't played with much is remote connection via my PSP but that's the next thing on my list to explore.
Try to be reasonable... its easier than you think...