Does anyone know if there are any long term maint. issues with HEV's I.e. Batteries, mechanics of the HEV system? We are considering getting a second Altima (HEV) but I am not up on the current tech. Seems the batteries used in the Altima would need to be replaced at some point down the road.

Yes, the hybrid batteries will need to be changed. It is estimated at around 8 - 10 years. The dealer offers a 10 year 100,000 warranty for the hybrid system so as long as your not planning on keeping the car over 10 years you should be ok, and since the 2007 and 2008 hybrid models use the Toyota hybrid technology which is proven there shouldn't be many other mainenance issues. Well I hope not anyway.

Love my hybrid so far...but then again, I came from a 7 MPG 4x4 truck.