while I dont have any direct advice, Ill say whats been the conclusion of my experience with the topic:
#1. If someone wants something bad enough, they'll get it.
#2. If they want it that bad, its not worth your life, thats why we have insurance companies.
#3. Time is your friend. The biggest, thickest, hardest metals can still be cut, but if you have two of the smaller type - it will probably still take longer. Me, Id rather have (4) 10$ locks on my bike then (1) 40$ one.
I make my stuff the slightest bit harder then whats sitting next to it (to take) and the hope is the opportunistic criminal will often pass it by in favor of the chump that did nada to protect his goods sitting next to it.
If its a pro, or a group of em, and they want it - they'll get it - its just a question of how much $$ in locks and gear do you want to pick up off the ground when they're done?
As you can see from my (albeit a bit glass-half-full) theory above, there is no one answer. I would start by asking what your predicament is (apartment, home, home with garage, etc..) and where you like to park your machine.
One of the least expensive investments I reccomend is the cheapest bike cover you can find, the best one I've owned cost 20$ from a tourer friend of mine, and was beaten to crap but was only a year or so old. That cover, combined with a 4$ bicycle cable lock from wal-mart was like an invisible shield around my bike.
Granted I dont really go anywhere too treacherous, which is the best way to prevent anything is to not let it out of your sight.
Im rattling on but this is a topic that has been discussed quite a bit. Id recommend doing a search on it then come back after you have read some more info. Its almost as religious as oil discussions so be careful, but you should have all the info you need right here. Welcome aboard!