I actually would not recommend the iBook for running LabVIEW. NI has
stopped supporting powerPC-based Macs, so unless you have a copy of LabVIEW 8.5, you won't be able to run it.
The Dell laptop looks pretty good. Realize, however, that it's only a 600MHz processor. You won't see amazing performance out of it, but it will work. Expect builds to take around 2 minutes.