Here's a useful utility - import your existing email archives into gmail to use the powerful search feature to its potential. Gmail's not missing much now. A powerful synchronize tool for contacts, and a calander/to do list would make it the ultimate PIM tool.... although being able to link booby up with it would get booby closer to the ultimate PIM tool, with the addition of better privacy.

Now, if they would just update Google Desktop Search to search your Gmail too, as well as your Firefox history, GAIM conversations, media tags and all the ASCII files on your disk, allow custom community created filters for other files and allow you to link indexes on multiple computers, then the rest of the 'desktop search' world would never catch up. Take your opportunity google. Push the envelope of desktop search like you did with search and email.
Mark Lyon's GMail Loader (GML) - Import Your Mail into GMail