It depends what you are doing, since Biomedical Engineering covers a wide range of disciplines. My interest is in signal processing, control, instrumentation, system identification and parameter estimation, so the Signal Processing, Wavelet, Control Systems, Optimization, Global Optimization, Satatstics and Machine Learning, and System Identification Toolboxes are those I depend most heavily on, and others that I use when the situation requires them.
I have friends and colleagues who do image processing, robotics and rehabilitation engineering including mechaincal and structural engineering, heat transfer, diffusion, biochemical kinetics, and a number of other research areas, so their needs would not necessarily overlap mine.
I am certain a number of other prople will offer their own perspectives from their own interests and experiences.
