Try out the brilliant Dropbox service for 2GB of free Sync’d storage – that could prove really handy.
I would use CalDav along with Google calendar and iCal to sync my Calendars (if not going for Mobileme). You could also set your e-mail up to go through Gmail, harnessing the IMAP protocol to sync the read / unread / deleted status of e-mails in your account across both the laptop and desktop (and any other client you throw in)..
I think most things MobileMe does can be replicated if you’d rather geek out than spend, overall. It’s just a question of how you view the time spent / money trade-off.