Time Capsule from PC to iMac

1. Yes, it is. You would connect to your Time Capsule as though it were a network drive on your Windows machine and copy the files manually.

2. I'm not sure I fully understand your question, but you will be able to copy those files that exist on the Time Capsule onto your Mac. However, once the files are on your Mac, they will be backed up to the Time Capsule if you use Time Machine on your Mac.

The way Time Machine backs up to a Time Capsule is by creating a disk image called a sparsebundle. It has no way to distinguish if a file that exists on its hardrive outside of the disk image is the same file that resides inside the disk image, so technically you'll have two copies of that one file.

As a side note, you should never rely on the Time Capsule backup as your sole backup. It can fail, and if it does, so do your backups. If you have any sensitive or vital data that needs to be backed up, it should be backed up to more than one place. If you want to be extra careful, you should also be sure to use a cloud backup or an offsite backup in case of theft, fire or other disaster.

Honestly, if you're only copying the files over once (per machine) I wouldn't worry about it. You can hardwire your Mac or Windows machines to the Time Capsule to speed up the initial transfers (and the initial Time Machine backup for your Mac).

If you hadn't already purchased the Time Capsule and if you had an existing router, I would have suggested getting a Synology NAS as those are full featured NAS units with the ability to use them with Time Machine. But seeing as you already have the Time Capsule, you should be fine using that (in conjunction with another form of backup preferably).

Edit: I should have clarified earlier, but the only way to connect to the Time Capsule is via Ethernet or Wi-Fi. You cannot use the USB port to connect it to a computer to access the drive. So any transfering of files needs to be done over your network.

I would get either the DS112j (one bay model) or the DS213air, DS213+ or DS212j (two bay models). You can view their whole lineup at http://www.synology.com

You can buy practically any 3.5" hard drive to use with them (though I do recommend HDDs designed for NAS use, such as the WD Red), and depending on the number of bays, you can RAID the drives together into a larger volume.

For example, you can buy a 3TB HDD to use with the 1 bay model, or you can buy two 1.5TB HDDs and use RAID0 to make 3TB in the two bay models.

I have two Caviar Black HDDs I use in a NAS server, though I've repurposed them for NAS use and I would have gone with lower power consumption models if I'd bought them for my NAS from the beginning.

Edit: As for your Apple TV question, I do believe it needs to be jailbroken in order to be able to stream from a NAS, though I'm not too experienced with the newer ATV.

Sounds great. Just a couple of things though:

1. You mentioned you wanted 3TB of storage. The 2 x 3TB drives in RAID0 will give you 6TB. If that's what you intended, ignore this. If not, it may be cheaper to get 2 x 2TB HDDs for a total of 4TB in RAID0.

2. You will need to back up any files stored on the NAS. You can use the NAS as a backup for your Mac, but if you're using it to store your media files rather than on your computer, those will need to be backed up elsewhere.