I often think about the shuttle program in relation to all these crazy complicated, wildly expensive, and incredibly fragile space telescopes we're sending to LEO or the Earth-Sun L2. Would be damn useful to be able to repair/upgrade these things like with Hubble.
Obviously I realise the shuttle program was pretty far away from being able to head out to the Earth-Sun L2(AB, and wasn't even working towards it. But man, it would be nice to have that ability.