Hi sam7,

If you want real speed, you might want to check into the new Solid State Hard drives. They come in many flavors (USB, Firewire, PCMCIA) and both the read and write speeds are far above the fastest Firewire drives. There is no spinning platter, so the data has a much longer and more secure lifespan, there is much less heat also.
The downside is the cost, right now they are a tad pricey. You can check both tigerdirect and newegg, they both have many models available. I'm waiting for 3 things right now>

1. The cost to come down
2. A portable enclosure without need of a power supply
3. Making sure that the drive doesn't suffer from the Windows format problem (for example, a 500 GB drive formatted for Windows loses almost 90 GB. Frustrating!)

Good luck, hope this helps,
Ed