Most of Leica M worth their prices.
M1, M2, M3 are mostly collector than for use.
M4, M5 good bang for the buck
M6/limited edition had a new generation of Rangefinder viewer finder so it's really worth it's price.
M8 was total crap, the APS-C sensor and back menu was shit and that's why it's worth around 1500$ today
M9 first full frame insane shit.
The thing you have to keep in mind with Leica M cameras, is that it's high priced because of 2 things. The lenses you can put on it and the rangefinder.
As for hasselblad, not every model worth something. if you look at old 500CM, at around 500$ you can get a full package with a 80mm F2.8 lens.
The ones that worth a lot are the 503CW series. First because you can find some red/gold, blue/gold, green/gold, etc.. limited edition still new in the box so as a collector it's worth a lot.
For uses, the 503CW still worth a lot because it's compatible with current Digital Backs wich can become very nice if you want to get a high grade Digital Medium format camera for under 10 000$ Especially with blad or zeiss lenses.