Under Construction

2016 update:
Best hard drives and storage devices of 2016 - CNET
The Best External Desktop Hard Drive | The Wirecutter

Following are external hard drives with both USB and firewire connections.
Mac's require firewire if you want to boot from an external drive (handy if your internal disk goes bad in the middle of a critical prject; assuming you have been backing up your files.)
For extra storage space a USB 2 drive (480 Mbits/sec) will be OK. Firewire 800 (IEEE 1394b) has a maximum transfer rate of 800 Mbits/sec.

These transafer rates are maximum burst rates, actual speed will be slower because of the protocol overhead and extra bits (start bit, stop bit, ...) required in serial transfer. USB has more overhead than firewire, so a USB 2 (480 Mbs) will actually be slower than a firewire 400 (400Mbs).

Typical Sustained Data Transfer Rate (STR):
See also Data Comm Interfaces
FireWire 800: 40-50MB/s (2.5" 5400 rpm drive) 75-85MB/s (3.5" 7200 rpm drive)
FireWire 400: 30-40MB/s
Hi-Speed USB 2.0: 30MB/s
  I got 11 MB/s from my 1GHz macBook G4 to an iomega LDHD250 on a mac formatted partition
  and 8 MB/s to a FAT 32 formated partition
eSATA II 120 MByte/sec
USB 3.0 - max. 625 MB/s
Thunderbolt 2- max. 2,500 MB/s
Note: Actual thruput is lower than the maximum spec.
USB 3 and Thunderbolt 2 were about the same (115 MB/s) with a HDD (Hard disk)
With a SSD (Solid State Disk) Thunderbolt was faster (188 MB/s vs 167 MB/s Read)
and 370 vs 167 with the Aja Video Systems benchmark. Source: How fast is USB 3.0 really? | Macworld
Time to write 20GB - Thunderbolt 23 sec on SSD, 55 sec on HDD; USB 3 110 sec on HDD
Source: Thunderbolt vs. USB 3.0: | gizmodo.com

Formated as FAT 32 vs OS X Extended journaled USB 3.0
Copy of 2.45 GB - Speed is Bytes/sec so bits/sec is about 8 times more. <
Format 2.5 disk 3.5 disk
write readwrite read
FAT 32 18MBs 66MBs
OS X 62MBs 77MBs 62MBs 81MBs
Time includes 3 sec. of initialization before copy starts

Standard external drives use 3.5 " drives and with case are about 6.3 x 6.8"
Compact external drives use 2.5 " drives and with case are about 3.2" x 5"

Prices Nov 2014:
SSD (Solid State Drives) -
LaCie 250GB $300 Size: 3.5 x 5.5 x 1"
Elgato Thunderbolt Drive+ 256GB $379-449 Size: 3.3 x 0.8 x 5.2 in
LaCie Rugged Thunderbolt (500GB SSD) $500

PC World and cNet Reviews 2008:
The following got good reviews:
Standard (3.5 " drive)
LaCie d2 Quadra 500GB $200
Western Digital My Book Pro Edition 500GB $230
Seagate FreeAgent Pro 500GB $150
Iomega 400GB $350

Compact (2.5 " drive)
LaCie Rugged All-Terrain Hard Drive (compact) 160GB $130
LaCie Rugged All-Terrain Hard Drive (compact) 320GB $200
Western Digital My Passport Studio (compact) 320GB $200

Network attached storage (NAS)
These are file servers and sometimes media (music, video) streaming devices that connect to your network and run independently of a computer.
See NAS in networking.

Media and Data Servers:
LaCie Ethernet Disk Mini - Home Edition (500GB) $110-200 [6.7]
Iomega StorCenter NAS drive (250GB) $200 [6.3]
Media Only:
Apple TV (160GB) $320 [8]
Data Servers only:
Iomega StorCenter Pro NAS 150d (2TB) $750-800 [7.8]
Western Digital Essential Netcenter Network Hard Drive (250GB) [6.8]

Prices 2007:
Item eBay
Amazon ClubMac MacConnection Costco
LaCie 250GB Mar '09 $83 $90 $106 $110
Seagate FreeAgent™ Go 250GB $75 $79 $88 $90 $80
Shipping free free $5 $10 $5
Shipped from ?? S. Calif.
Consumer Reports Store Ratings Aug., 2006:
Amazon (90), MacConnection (90), CDW (87), Costco (87), MacMall (84)
Stores: Price: Better.: Amazon, Costco, MacConnection, MacMall; Average: Office Depot, Staples, Best Buy, Fry; Worse: Apple Store, Office Max, Circut City

ATA - Advanced Technology Attachment EDSA - Enhanced Datamover and Storage Accelerator eSATA - External SATA 3Gbit/sec (150 MByte/sec) ESDI - Enhanced Small Disk Interface HDD - Hard Disk Drive IDE - Integrated Drive Electronics later renamed to ATA NAS - Network attached storage RAID - Redundant Array of Independent Disks SAN - Storage area network SATA - Serial ATA SSD - Solid State Disk or Solid State Storage Device (e.g. flash or thumb drive) STR - Sustained Data Transfer Rate USB - Universal Serial Buss

See 2016 links above
PC Hardware
Mac Hardware
External Hard Drive Reviews at ZDnet
NAS - Network attached storage at ZDnet
Data Comm interfaces
Flash Memory Cards and drives
Hard Disks at wikipedia
Hard Disk Drives: 3.5" or 2.5"?

last updated 3 Nov 2014