P45 boards are rock solid. You really cant go wrong with it, at all. Be it ASUS, MSI, Gigabyte. They are all good.
As far as the Nvidia chipsets go....its really a coin toss. And I really mean that. You have about a 50% chance of getting a board that actually works, in terms of memory issues and massive voltage issues with overclocking.
Check newegg.com for prices and parts. They have the largest selection of everything.