That's a lot to pay for sentiment. You'd be risking several lives for sentiment, too.

For that matter, given the very narrow weight and balance limits on the Shuttle - especially for landing, I'm not certain the Hubble could be retrieved. I suspect the answer is yes* but don't have a definitive answer. I don't know if you could fold up the solar panels, so they may have to be left in orbit. Would other things also have to be removed, such as the high gain antenna?

*The reason I say this is that, had the Shuttle had to abort it's launch in 1990, it would've had to be able to land with the HST on board at an emergency airstrip. Still, there are other factors that cause the center of gravity to move, such as consumed propellants. From what I've read, the CG range of a Shuttle is only a foot or so from most forward to most rearward limits. I'd also need to check the HST's weight and see if that's within the Shuttle's normal (as opposed to emergency) landing limits.