Why is the partition so Large on the Inspiron

I have a new 1505 with a 100GB hard drive. The "D" Partition is over 20
GB's in size. OK so there's the XP Home restore as well as some of the
other garbage that you have a couple of days to renew. But why is the
partition allocated 21 GB that is insane. I have an HP desktop ( I hate
it) and it has the operating system on a partition but it's not close
to the % of the total as the Dell.

I'm almost inclined to just go out and buy XP pro and re-write the
whole thing. I did the "chat" with some knucklehead at Dell and they
say it's the system restore and I'm like "OK but why 21 GB's" and they
could not give a coherent answer.\

Anyone with any experience with this? There is NO WAY the bundled
software could use this kind of space up. There's not picture, digital
movie or sound files. I do not understand this at all

Thanks for anyone's help

Barry