I received a review unit of HP's new StoreEver LTO-6 Ultrium 6250 tape drive a couple of weeks ago, and have been very impressed. Street price is about $3000, and it can store 2.5TB of uncompressed data to a single tape. Tapes cost about $70 each, but are known to drop to about $30 each within a year or so of a new LTO format's introduction. And with a miniSAS connection to your computer, the drive can read/write data up to 180MB per second. The unit's small enough to fit under my Apple Cinema Display, and it's surprisingly quiet as it works.
I'll have a full review on Creative Cow in less than two weeks, where I'll also look at BRU PE 3.0 archival software for the Mac.