Lego Trains goody buy?

Any of your Lego buffs out there have the Lego trains.  I am thinking of getting one for my son for Christmas.  He is a huge train fan.  He still plays with his wooden Thomas trains, but has more interest in electric trains.  He is also a huge lego fan.  I figured two in one.  I know they can be expensive but he would definately make it worth the cost.  Any thoughts or reviews on the Lego trains?