We are in the process of developing analysis pipelines for WGS,RNA and Methyl-seq data. The first projects considers 100 patients with a common disease. All the analysis would be run on data from these patients. Our institute's computational center is offering us 5 nodes (24 CPU core, 2.6GHz clock speed, 128GB RAM memory each), I believe that necessary storage space would also be provided to us. Based on your experiences would you please tell me if having 5 nodes is going to be sufficient, I understand that there cannot be one single answer to this question but any help from you all is much appreciated.  
Since you appreciate that there can't be one right answer here you are off to a good start. 

Your requirements will/may change over time and you should build some flexibility into the allocation to access nodes with better specs (mainly RAM) in case you find that you are unable to complete some specific analysis. This recommendation assumes that no *de novo* assembly work would be involved since the specs (mainly memory) would be insufficient for that type of analysis.