If you are waiting for Merom, i would just take the plunge. I personally don't forsee that they will be put into MB's till next year. Currently, there is no big distinction between the MB and the MBP except for the screen size and the descrete graphics card. And that right now dosen't warrant $600+ dollars. So we need to a distinguished factor, a faster processor.
But if you are a student, it's a good time to buy. Apple is giving away free stuff after rebate. Even if you don't need it, it makes a spiffy gift. Perosnally i'm going to go and get one this evening. I'm going to get the MB 2ghz white w/ 1gb ram. And picking up a 30 gig video for $90 after rebates and a printer. So w00t!