we have got to get a sticky on external drives.
it is very popular and it seems that a consensus has been reached.
1. It is cheaper and still very easy to buy a HD and an enclosure separately.
2. Segate offers the longest (5 year) warranty and is seen by most as the best option.
3. Dont bother with anything smaller than 150gb as it is not cost effective.
4. USB is fine for strict backup drives. FW400 is preferred for constant data access like games, photos, songs, videos, and even an OS. FW800 has not been proven to be significantly faster than FW400.
5. Make sure to match drive and enclosure types (ide&ide, sata&sata, pata&pata)
6. Enclosure chipset does matter but you will pay for it. MacSales.com sells enclosures with the Oxford chipset starting at $60. Enclosures with 'slower' chipsets can be found as low as $20.
7. Look at Newegg.com, Outpost.com, CircuitCity.com, and others for Seagate drive deals.
8. Avoid TigerDirect.com rebates.
I just did this on the fly so I apologize if it jumps around a bit. Please add any other general advice.