I would say no if it works good because I think normal GPS units are starting to get redundant as smart GPS phones are becoming more and more common these days. Because if you go for an Android OS phone, you can get google maps street view (as long as you have a data plan) and voice guided directions.
But it's up to you, if you really want lane guidance, 3D images, junction view, and other fancy stuff.
I know this is further down the track, but I have recently been contemplating the same thing.
My 260W is still great and working well...but I would love a GPS that has the traffic live update feed so that it routes me away from the more heavily congested areas. That's the killer feature for me.
I have been looking at the Nuvi 3750 recently. It has optional live updates though...which I am not sure about...but still has the text to speech which is what made me shell out more for the 260W at the time.