bill,
Good idea about waiting until the summer.
I won't make a current recommendation, since you're waiting.
However, I will speculate. Most likely, there will be a 13-inch widescreen Mac Book by the summer that will replace the iBook line, but it will look similar. My opinion is they'll have a couple models, a $1000 model and a $1200-$1300 model. Keep in mind you can get another $50-$100 off these prices, with your student status at that time. The higher-end model will probably give you slightly faster machine and bigger hard drive. This should be a very popular and very capable machine. I think we're all going to want one.
Once in the summer, I'd suggest you wait until Apple starts up the Student Union promotion again. With that promotion, you get the normal discount on the computer *plus* they'll give you $150-$200 towards an iPod. They've done it for the past three years or so, they say its successful, so hopefully they'll do it again. If you already have an iPod, you could always sell the one you get from the promotion to go towards the computer. Otherwise, you get a new computer, and an iPod thrown in for not much more, with the promotion. Hope this helped a little. You're going to enjoy your Mac.
Many think they'll discontinue the professional smaller than 15-inch portables (i.e. there won't be a Mac Book Pro smaller than the current 15). However, if they did surprise us with a Pro 12 or 13-inch machine sometime this Spring, you might consider it too. It would still come in under $1800, but again be another step or two above the Mac Book.