While there are a number of online services available for sharing documents, photos, videos, and other items on your system, unless you manage all of your content through these services then the data on your system is still fairly confined to your computer. For instance, if you create a movie project on one system using iMovie, while you may upload the final product to YouTube or another service to share, the files used to create the movie might be gigabytes in size and be scattered around various locations on your hard drive.
If you decide you would like to move these files to a new system, then doing so through an online service might be a frustrating experience, either because of slow connections or because of file size or transfer limitations. However, if you have a collection of smaller files, then the use of an online option may be the best approach.
You can take advantage of numerous available options listed below, each which has its benefits and drawbacks.
While much file sharing is moving to Internet and local networking, most computer systems still ship with DVD writers that can be used to burn a data disc containing the files you need to transfer. Unfortunately given other connectivity options, this is not the quickest way to move data, but is still an option that can get up to 8GB of data moved to a new system or otherwise archived. Once burned, then the disc generally is a good long-lasting storage medium; however, disc burning is relatively cumbersome, takes a while, requires a supply of blank media, and requires care to prevent damage to the discs.
Best uses: Burning movie DVDs, disk images, or archiving data
Another commonly used option for transferring files from one machine to another is e-mail, when you simply append a file as an e-mail attachment in a message to yourself, and then retrieve it on the second system via Webmail interfaces, if you do not have a local email client application installed and configured. While such file transfers can be quick, especially with push services, the drawbacks to this are that many times there are data size limits for attachments, or bandwidth limits that make this option impractical for larger files.
Best uses: Smaller data sets, about 20MB or less
As broadband connectivity gets more widespread and higher bandwidths become the norm, the use of online storage options like Dropbox are being used more frequently. These require Web access, and as with e-mail they offer an easy option that is very similar to e-mailing yourself a document or two, but are limited by bandwidth and overall storage capacities. Even a fast 10Mbps upload connection will result in about 70MB per minute at optimal speeds, which can take a while to transfer gigabytes of data, should you need to do so. However, in most cases for managing smaller file collections, the ready availability and cross-platform support of these options makes them quite appealing.
Best uses: Up to a few hundred MB at a time
USB thumb drive
One of the most popular and cheapest options for file transfer is the use of thumb drives, which offer the same functionality as CD and DVD media, but are exceptionally cheap, convenient, and easy to repeatedly use. The main problem with thumb drives is how easy they can be lost or damaged, but beyond this the USB transfer rates trump most online options when handling larger files.
Best Uses: Up to a GB at a time
External hard drive
As with Thumb drives, you can also use an external USB or FireWire hard drive if you need to transfer larger files. While thumb drives come in sizes up to 256GB or higher, these can be expensive options, where the same size in a conventional HDD format will be a fraction of the cost. The one drawback to both USB and external hard drives is the formatting requirements for both OS X and Windows. The best option for use with Mac systems is to use Apple's HFS+ (Mac OS X Extended) format, but for most compatibility you would have to use the old FAT32 format if you need to use the drive on both OS X and Windows machines.
While most external hard drives are USB or FireWire based, some use the Thunderbolt options available in Apple's latest Mac systems, providing far greater transfer speeds.
Best Uses: Up to numerous GB of data.
Local file sharing
The final option for transferring files between systems is to use local file-sharing services, which besides Thunderbolt-based hard drives will provide the fastest means of data transfer by far in terms of throughput, and are best used for most file transfers on a local network.
The fastest option for local networking is Ethernet, but if you do not have an Ethernet connection option, then you can also use Wi-Fi networking to perform the same tasks, though at slower speeds (about a 4th slower for 802.11N and around a 20th for 802.11g).
The basic local file-sharing setup in OS X is fairly simple. First open the Sharing system preferences pane, followed by checking the box next to File Sharing to enable it. Once done, you can click the Options button and enable Windows file sharing or FTP file sharing, but for transfers between Mac systems these options are not needed.
With the file-sharing service enabled, as long as both Mac systems are connected to the same network, then they will be able to broadcast their available services to each other. With Ethernet, this can be done by simply connecting the systems using a basic CAT-5 cable (the shorter the cable, the faster the average speeds will be), or by enabling Wi-Fi on both without connecting to a network. These options will create an automatic Ad-hoc network between the systems that will suffice for the data transfer.
When the network between the systems is established, by opening a Finder window on one system you should see the second computer located under the Shared section, and clicking it will provide you with options to connect, mount an available shared folder, and transfer files.
If you are running OS X Lion, then you can take advantage of Apple's new AirDrop sharing option that can be quickly used to transfer files between systems without much setup at all. To use this, just go to the AirDrop section of the Finder's sidebar on both systems and each should show up in the other's Finder window. From there you can drag files to the system of choice to initiate the transfer.
File sharing via AirDrop is meant to be done via Wi-Fi connections; however, you can enable it to use Ethernet by running the following command in the Terminal (available in the /Applications/Utilities/ folder):
defaults write com.apple.NetworkBrowser BrowseAllInterfaces 1
When this command is run, then the various options for local file sharing can be accomplished using either Wi-Fi or Ethernet networking; however, if both are enabled then the system will preferably use the system's primary connection, which in many cases will be Wi-Fi, resulting in a slower connection speed than if Ethernet is used. While you can adjust the network service order in the Network system preferences so Ethernet is given priority over Wi-Fi (a setup I recommend), this might not always result in the system using Ethernet for the transfer, especially if the connection is already established over Wi-Fi.
Instead of changing the service order or other settings, you can instead force the system to initiate a transfer over Ethernet by temporarily turning off Wi-Fi on one or both of the systems using the Wi-Fi menu extra. First ensure the systems are connected via Ethernet, and then turn off Wi-Fi before using either the Finder's sharing or AirDrop to connect.