consider this (Score 1)

i work for a company that develops Rx systems for hospitals. We faced same design decisions, so here is what we found: if your product is going to interoperate with other healthcare software, you will probably have to work with HL7 (the standard protocol for healthcare data exchange). The easiest we found to do that is BizTalk 2004 with HL7 accelerator (yes, both are Microsoft products). So .NET was the natural choice for this component. The rest of the system components are written in Delphi though, so you might want to consider this one too as a grat RAD tool. Good luck!