Okay... Bad Sector, bad choice of words. What I ment was one un-recoverable error with the drive (be it a sector that can't be moved, or was in a spot where OS files where damaged and could not be recovered, or the drive suffered a physicall failure).
I have had my my personal TiVo upgrade drives develop bad segments that nothing could repair (one time a two week old drive "threw a head"). In one instance I lost 10 recordings of Smallville and I have never caught up. (I have all the DVDs just haven't watched them).
I just wanted to point out that spending that kind of money to use two 500gb drives, opens a wider single point of failure, based on how the "marraige" of the two TiVo hard drives work.
I am not against having a Terrabyte of storage, in fact I would love to hook a SAN up to my TiVo if I could...
I try as best as I can stay on the cutting edge of stuff, and make sure that I don't always see one side of the puzzle.... Because if I do get too focused, then the next guy coming up with bigger eyes will push me off the ledge and I will never see them comming.