External Hard drive for Early 2008 iMac

I'm looking for recommendations for the best external hard drive to use with an early 2008 iMac running OS X El Capitan 10.11.6 using a Firewire interface:

Hardware Overview:

Model Name: iMac

Model Identifier: iMac8,1

Processor Name: Intel Core 2 Duo

Processor Speed: 2.4 GHz

Number of Processors: 1

Total Number of Cores: 2

L2 Cache: 6 MB

Memory: 6 GB

Bus Speed: 1.07 GHz

Boot ROM Version: IM81.00C1.B00

SMC Version (system): 1.29f1