Sorry no. I'm certain Apple will kill the white MacBook completely in the next refresh. They won't be expanding on a dead product. The product is pointless now with the amazingly affordable MacBook Air.
Well, sort of. The MacBook Air is not a comparable product to a white MacBook. Yes, it's super popular, but for the exact same price you get a faster CPU and a screen that's larger by 2". You also get RAM expandability, an optical drive (still important to alot of folks), and by adding a little more to your cost you can really SMOKE the Air by dropping in an SSD. When I order my MacBook here soon, I'm going to get 4GB of RAM and a 128GB SSD, my grand total (including the laptop) will be around $1,400, similar in price to a 13" MacBook Air configured the same, but with a faster CPU, longer battery life, and optical drive.
The white MacBook is a VERY popular MacBook, they probably won't kill it. If they do, they will still offer a $1000 or less spinning-hard drive notebook of 13" or larger. Right now, it's a great lineup. If you have a $1000 budget, you have the choice of a high end, super light netbook (Or rather, a laptop with a Netbook size screen, but laptop performance and laptop quality screen), or a slightly quicker, slightly larger notebook with a couple extra hours of juice.
I don't think the Air is a replacement for the MacBook.
I, personally, think 11" is a bit too small. It's kind of like the 7" vs 10" tablet debate, technically it's really close in size but it's enough to make a difference. Like a 7" Tablet, the Air offers additional portability, but for some users, limited functionality (other uses don't feel a difference). For others, myself included, 13" is a perfect size. It's big enough to be productive with multiple windows, yet small enough to remain portable (anything bigger is too big, I've been using 14" laptops for forever and LOVE it.) Once again, if you wanna go 13" with the air, your gonna spend $1400. (well, $1,300 if you don't get the RAM upgrade).