If your project is going to require a serial or parallel port interface, I would recommend that you learn LabView. Programming the serial or parallel port interface is definitely going to be easier in LabView, and even the GUI programming will probably be easier in LabView.
VB is good if you need MS Access kind of database and if you use any ActiveX. The Serial and Parallel ports can be accessed through VB too. If you are going to use any special hardware like RS485 to RS232 converter, Mod Bus etc, you need LabVIEW. LabVIEW is having good support for instrument controllers and Addon cards. If you feel that your hardware may grow and you need future support then best choice is LabVIEW.