The PS2 titles, GTA3 in particular were so revolutionary for their time that there is NO WAY they could be overrated. As a matter of fact, they're probably not appreciated enough in that aspect.
GTA4 and now GTA5, I suppose you could argue that they are but, when you look at what you get for $60.00, it's hard to do that. I mean, the replayability is through the roof.