iTunes can be a useful, but it can also be a huge pain. If you've ever used it for sync, you've likely experienced problems. Fortunately, with the help of a few apps, you don't ever have to sync with iTunes again.
Regardless of how you want to view your photos and how you want them on your phone, you have quite a few options. Recently we looked at how PhotoSync for Lazy makes for quick, automatic photo syncing with your Windows PC. Photo Sync is a cross-platform solution that lets you wirelessly copy your photos from your iPhone's camera roll onto your computer. Apps like Dropbox are a good way of syncing photos cross-platform as well, but viewing on your iOS device isn't all that great since the Dropbox app doesn't provide any kind of thumbnail previews. You can flick through photos one by one, however. If you're a Flickr user, Photo Wallet will sync your Flickr photos wirelessly (called Photo Pad for iPad users). iPicasa does the same thing for Picasa users. While not every single base is covered with photos, chances are you use a service that'll easily let you avoid syncing your photos with iTunes.
Although you might think video's more difficult, it ends up being pretty easy. You can either use Dropbox to sync and save physical copies of video files on your iPhone or you can use video streaming applications like StreamToMe, AirVideo, and Libox (our overview) to watch your video (that's stored on a home computer) anywhere you have a decent connection.
Music is really where the most concessions come in, but you do have options. While, again, Dropbox will let you save files, that will get annoying fast when you have thousands of songs you want to store. StreamToMe will let you stream your music from your home machine, or you can use any of the great music-streaming services that have iOS apps (some of which are free). Unfortunately, though, if you want true music sync without iTunes you'll either have to resort to jailbreaking your iPhone and hacking together a syncing process without iTunes using WinAMP and ml_ipod.
Podcasts and Spoken Word Content
Podcasts and spoken word content are fortunately a bit easier to handle than music. If you're an audio book listener, chances are you get your content through Audible. The Audible app lets you purchase and download audio books directly to your iOS device over Wi-Fi with no need for iTunes. Alternatively, Apple's iPod application, in conjunction with the iTunes Music Store, lets you update your podcasts manually and purchase much of Audible's audio book content. While these third-party apps tend to do a better job, when it comes to spoken work content you can get by with what's already included on your iPhone.
For contacts, calendars, email accounts, tasks and notes, you can always make use of Apple's $119/year MobileMe service or just use Mail2Web instead. There are plenty of individual app alternatives, however. Air Sharing lets you transfer and view files over Wi-Fi. Dropbox lets you access anything you keep in your always-syncing Dropbox, with the option to save files directly to your iOS device without trouble. Simplenote is a great option for syncing plain text and Evernote can handle richer text with graphics. The list goes on and on because there's really no shortage of apps for wirelessly syncing documents and similar content.
Got any great ways of breaking away from iTunes while still satisfying your syncing needs? (You know, besides getting an Android.) Let's hear 'em in the comments.