I prefer buying a good case and select precisely the drive which I view as the best for me, not getting whatever the external drive manufactured found the best for his business.
I liked the OWC cases (quad-interface for SATA, triple-interface for PATA), but I got the PATA and I found putting the screws to the drive just a bit tricky.
Then I needed a SATA and I wanted a quad, but didn't want to pay for international courier shipping, so I sourced a quad Macpower locally, and I like it better (the shielding, screws easy to fit). It seems very well made.
Last time, for the drive I went for a Samsung F1 (1TB) which is fast, power/thermally efficient and cheap. But they only give you 3 years warranty. Seagate gives you 5 and it's true I get a warmer feeling. Sometimes I buy from them, when I think it's the best model for me (the new 1.5 TB is a candidate for my next time soon).