Actually, i meant VNCing to the VM from a laptop.
VNCing from the same comp would have no sense as the keyloggers/screen capture/mouse movements capture would kill it.
Right. But if you use VNC from a different machine, why not just run your VM there? Or vanilla Bitcoin? Since you are assuming that that machine is and remains clean, otherwise using VNC from there is just as pointless. It would even increase security since you seem to assume the original VM/VNC host could be compromised.
The "separate minimal machine for Bitcoin only" is of course superior to everything.
Definitely, if you have a sizable wallet it's worth it. If Bitcoin really takes off there will be businesses around this putting something on a cheap device, maybe smartphone.