If you really need a DVD burner, then the 12" iBook is out of the market. Only the 14" iBook and all the PowerBooks have a SuperDrive. (CD-R/W DVD-R/W) (Thats + and - R/W for both)
So that leaves your option with the 12" PowerBook.
The G5 laptop will probably never happen, too much heat, and the Intel ones may be a while yet.
If you need a new laptop, go for it. You can guarantee that whatever you decided, and whenever you buy it, the next best thing will be around a couple of months later.
Screen quality on both machines are excellent, recently improved, and battery life is acceptable.
Check out the Apple store for comparisons

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