Leave them up and hope that we gain a fuller knowledge about ourselves, and history by their existence.
Paint over them and try to hide from our past.
I was in Minsk in 2000 there was debate amongst the people I was working with about whether or not the road signs and squares should be renamed back to the pre soviet labels. 80% of the city was built post WWII, so any 'return' to the old names was a bit farcical, but it could also be argued that the soviet era names were just as illegitimate.
I see this as being far more clear cut. We did it freely, we celebrated it openly, therefore we should live with it.