I normally like to automate things, so I'd recommend MobileMe for syncing your contacts, calendars, preferences, keychains, bookmarks, mail, etc. in sync. As for iTunes or any other actual content, I'd say go with Dropbox. It will keep everything in sync for you (Or ChronoSync, though I think Dropbox is a simpler setup). The only advantage of CS is if you want thing to sit in their own place instead of copying them to the DropBox folder.
Read this if you like the idea of MobileMe but don't want to spend extra money on DropBox or CS:
If your music library is small, you can even use MobileMe's iDisk to keep things in sync. Just copy the iTunes folder to your iDisk (MM gives you 20GB to split between mail and iDisk). Once its dragged in there, you can turn on iDisk syncing on both computers, and it will actually sync your iDisk (cloud) to your desktop on both macs. Whenever you add a song to iTunes on one computer, iDisk (on your computer) will sync with cloud, and back to the other computer...