It may sound too good to be true, but it's actually just as easy to sync an Android phone with your Mac as an iPhone. Even better, the majority of syncing is done in the background for you, constantly, through Google.
The key to headache-free syncing between Mac and Android is to use Google's cloud services as a middle-man. Your phone's already designed around using Google for its mail, contact, and calendar data, so we're just going to show you how to sync those down to your Mac, which takes little effort. Once you've got it all set up, the only reason you'll ever have for plugging your Android phone into your Mac will be to sync music (and if you really want to, you can sync that over Wi-Fi too).
Setting up Gmail in Mail.app
If you just use a browser to access your Gmail account, then you don't need to worry about Mail at all. If you do use the app, you'll be happy to know that syncing it with a Gmail account is so simple that it's almost automated.
Syncing Your Contacts with Mac's Address Book
Open the Address Book, then open its preferences and click on Accounts in the top bar of the window. You should see an account called "On My Mac Local," which should already be selected. To the right of that is a check-box labeled "Synchronize with Google." Just check the box!
Syncing Your Calendars with iCal
In iCal, open preferences, then click on Accounts in the top bar. Click the "+" symbol at the bottom-left of the window. Leave Account Type set to "Automatic," then enter your Gmail login information. After you click Create, iCal will sync your Google Calendar automatically. If you use reminders or alerts of any sort in Google Calendar, you'll also want to click the Advanced tab in iCal's preferences, and check the box marked "Turn off all alarms." Otherwise, you'll be receiving double reminders.
Syncing Your Music with DoubleTwist
DoubleTwist is called "iTunes for Android" for a reason. Not only does it look like a miniature iTunes, but it performs most of the same functions, only for your Android phone instead of an iPhone. With DoubleTwist, you can sync music to and from your phone, whether it's song by song or a whole playlist. It's fast, simple, and free (which we like).
The DoubleTwist desktop app for Mac can sync photos and videos just as easily with the built-in media browser.
Sync Your Photos with Picasa Web Albums
Last but definitely not least are your photos. We're going to use Picasa Web Albums, since it syncs beautifully with Android. Many Android phones should be able to sync with Picasa out of the box. Just double check that all your Google services are set to sync by checking in your phone's settings under Accounts & Sync, and tapping on your Google account.
On the Mac side, you can either use Google'sPicasa desktop software to sync Picasa albums, or you can use the iPhoto to Picasa uploader. This iPhoto plug-in which will let you upload and manage Picasa albums by choosing File, then Export. If you've chosen to sync with Flickr, you can just hit the Flickr button in the bottom right hand corner of iPhoto's window to send any album to your Flickr account—it's already built-in.