Well i just received my first vertical battery grip for my D90 and i Love it! This thing is sweet and works like a charm! You just might want to get yourself one i don't think you'll regret it.
The Nikon MB-D80 Multi-Power Battery Pack holds 2 EN-EL3e Lithium-Ion rechageable batteries, effectively doubling your total shooting time. Can also hold a AA battery holder (included), so users can use AA batteries as a power backup. The MB-D80 Multi-Power Battery Pack provides an AF-on button, vertical firing release with lock, and front and rear command dials.