basically, the easiest way to copy your data is to buy an external hard drive. it doubles as a backup in case something happens. Copy your documents to the drive from the laptop before format, then copy them back when you get your laptop rebuilt/reformatted.
1 terabyte units cost well under $100 now. Some even come with backup software built in or included with the disk. For example, here's a 1tb western digital external with free shipping for $70.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136469
if you're on XP, you want to back up the following directories by default:
c:\documents and settings\username (whatever your username is). Under this directory, copy the following:
\my documents
\my videos
\my pictures
\my music
\contacts
\favorites [internet explorer bookmarks]
\downloads
\links
\saved Games [if you play games]
you may need to turn on option to view hidden files and folders under tools->folder options->view->'show hidden files, folders, drives' and also uncheck 'hide extensions for known filetypes'
this will display extra folders under your user profile. if you use microsoft outlook (not express), go into local settings\microsoft\outlook. if there's a large file called outlook.pst (or anything with .pst extension), copy that over. That contains all your mail within outlook.
In firefox, make sure to export your bookmarks into html.
This site has a hefty write up on this as well, but you can generally omit many things under \program files and \windows
http://www.argentuma.com/backup/system-backup.html