I've been testing the new Eye-Fi Pro card (and will report on it soon), but I still have an older Eye-Fi Explore card too. For those of you who also have older cards, I want to remind you that there's probably a firmware update waiting (especially if you haven't used the card in a while). For my Explore card, the update provided me with "selective transfer," a function I had wanted for a long time.
Basically it works like this: After the firmware update, leave the card connected to the computer and go to the Settings tab in Eye-Fi Manager. Click on Upload Settings, and change the preference from Automatic to Upload Selected. Save your settings and unmount the card. Now, with the card back in the camera, initiate uploads by marking the images you want to transfer with the Protect key. Only those photos will be transferred via Eye-Fi Manager.
After you're done with the Eye-Fi transfers, you may want to Unprotect your pictures. Some photo applications won't let you image edit protected pictures...