I agree with the others that Tim Finn is great, as is Before and After. Imaginary Kingdom is a strong album too. If you're not necessarily wanting to be completest to begin with, how about the anthology? While some of the songs are reworked (and CH/Enz), there's something of a selection across his solo albums save the most recent one (if memory serves), so that might give you a taste and help determine if there's an era that you like, since they're all quite different. Or, if you're a completest, why not start at the beginning with Escapade?