New External Drive best way to format?

[dmbmar]

FAT32 (File Allocation Table)

• Read/Write FAT32 from both native Windows and native Mac OS X.
• Maximum file size: 4GB.
• Maximum volume size: 2TB

NTFS (Windows NT File System)

• Read/Write NTFS from native Windows.
• Read only NTFS from native Mac OS X
• To Read/Write/Format NTFS from Mac OS X: Install NTFS-3G for Mac OS X (free)
• Some have reported problems using Tuxera (approx 33USD).
• Native NTFS support can be enabled in Snow Leopard, but is not advisable, due to instability.
• AirPort Extreme (802.11n) and Time Capsule do not support NTFS
• Maximum file size: 16 TB
• Maximum volume size: 256TB

HFS+ (Hierarchical File System, a.k.a. Mac OS Extended)

• Read/Write HFS+ from native Mac OS X
• Required for Time Machine or Carbon Copy Cloner backups of Mac internal hard drive.
• To Read/Write HFS+ from Windows, Install MacDrive
• To Read HFS+ (but not Write) from Windows, Install HFSExplorer
• Maximum file size: 8EiB
• Maximum volume size: 8EiB

exFAT (FAT64)

• Supported in Mac OS X only in 10.6.5 or later.
• exFAT partitions created with OS X 10.6.5 are inaccessible from Windows 7
• Not all Windows versions support exFAT. See disadvantages.
• exFAT (Extended File Allocation Table)
• AirPort Extreme (802.11n) and Time Capsule do not support exFAT
• Maximum file size: 16 EiB
• Maximum volume size: 64 ZiB

I'm confused by this. I have a home network with an iMac and several PCs. Each computer on the network can read/write off the hard drives of each other, including the iMac, which is formatted as Mac OS extended. So, if i hang an external off the iMac formatted that way, will both the PCs and the iMac be able to read/write to it?

My intent is to create one partition for time machine to backup the mac. The balance will be used for pictures / videos that I want to use on both the iMac and the PCs. I would backup this partition on a separate NAS. Will this work??