Here's the thing about this bundle: despite the fact that it says "special value" on the box, it's not the best value on a Beatles: Rock Band set you can get. If you want the superior Rock Band 2 instruments, you can get the RB2 bundle right now for $100. Purchase a separate Beatles disc, and you've got two games and one set of (nice) instruments for the same $160.
If you don't care which instruments you get, and you're planning to buy on 360 or PS3, you can go even cheaper and grab the $79 Rock Band/Rock Band 2 game pack, which includes the Rock Band 1 instruments and Rock Band 1 and 2. Throw a $60 Beatles in and you have three Rock Band games for the price of one Special Value bundle.
Of course, this information is mostly valuable for people planning ahead. The real place of the Special Value Edition is in stores, as a single box that makes an attractive impulse purchase.