I would get exactly the same drive I just bought: WD20EARS
That's the non-RAID, regular edition.
Especially if reliability is the concern.

The whole idea of the RAID edition drives, is to sacrifice error-recovery (aka. "reliability") for guaranteed response time in error situations.

Fast error response times are important for high-throughput transaction rates (eg. credit card processing), but 100% irrelevant and harmful for a home server.

And in non-error situations, the regular unit is one fast drive by any relevant measures.

I want the drive to try harder to read partially corrupted data. Don't you?

Cheers