Nope. Wireless G speed is the same. But it will future proof your system.
I currently have a Dlink Wireless G router that always disconnects on me. So i want to buy a new Wireless N DIR-655 router. All my wireless devices can only support up to G. I have a PS3, laptop, and a IPod touch. Will I have any benefits if i use these devices with the DIR-655? Will it benefit my computer LAN?