bvgs, I´d make up my mind about the running cost rather than the buying.
Airplane value stays more or less the same over some time, but costs for overhauls, refurb, avionic upgrades etcetc can eat you alive.
Why not charter out something nice? Navajo springs to mind...
Turboprops and Jets are expensive to maintain and for that sort of budget I´d doubt that you get the best mantained example of all possible when looking at TP and Jets. Mind you that EASA- CAMO is around the corner (deadline Sep08?)
and "cheating" on maintenance will be more difficult, and more important, things will get more expensive.
Decent sized Pistons are ageing. tricky one, I´d say.