its twice as bad in the graphics card industry where advances come so quickly that by the time a card is available in store the benchmakrs are jsut coming out of the other companies new card that demolishes it in every aspect.
Basically just look at what you need and get the cheapest thing you can find that meets your needs, or alternatively, figure out how much money you can spend, then get whatever is the best in that price range. Waiting for a new card or processor only makes sense in some certain situations. If you need a computer now its not gonna do you any good to wait 4-6 months to get a Conroe. If you already have a good system then you might as well sit on it till its outdated, maybe Conroe comes out and puts your rig to shame, so you buy that. If its just a bunch of Intel marketing then jsut sit on what you got till something better comes out in your price range. But there will always be something better coming, so if you just gotta have the best there is you better get a d@rn good job, casue that'll cost you some serious $$$ to always be on the bleeding edge.