Time is money?
Interesting blog by Rick about how Best Buy sell you extra's when you buy a laptop - I left a comment over there:
Coming from someone who is now 6 hours into the process of installing new hard drives on his 3 kids computers, installing XP, updating, installing office, updating, registering, etc, etc., I'd take that $129 offer right now.
Like you say, it seems ridiculous until you quote the hourly rate. I'll have spent $1,000 of my time to upgrade my kids computers. 
As an aside, I was chatting with friends the other day and someone said "Why on earth would you buy from Best Buy anyway? Everything is so much cheaper online". True, but when I want something it's usually because I have a need right now, not in 7-10 days.
And anyway, I proved yesterday that walking into one of these stores can get you some great bargains - I didn't know about these offers before walking into the stores.