For every measure there is a counter-measure. Use long random passwords, and now you have to store them somewhere. Now your password storage "vault" becomes target - use a popular one, and that makes it more likely that the bad guys will develop a crack. Use an unpopular one, and maybe it's not as strong as advertised - after all, why is it unpopular. I will encrypt them myself? well, if your computer gets compromised, don't you think the encrypted files are going to be the first place the bad guys look? after all, if it wasn't important/valuable, you probably would not have encrypted it.
Maybe you've found a completely secure and unbreakable password storage vault - now you have to worry about the passwords being captured when you use them. With a wireless network, it is not so hard - bad guys have devices called "pineapples" that are battery operated base-station like devices that they will hide nearby and will fool your computer into trying to connect - it will broadcast the SSDI of the network it is trying to penetrate - you computer will say "hey, there's that network that I'm supposed to automatically connect to, and send your long random password to connect, and now it's captured". Now, they can connect to your secure/encrypted network and start probing for other vulnerabilities...
I have a friend who does security audits for corporate networks (essentially tries to break into them with approval from the company). He has not yet found a network he cannot break into. He does not use wifi in his home. Personally, I think it is crazy to give up the convenience of surfing the web untethered because a highy motivated criminal can break into your wifi.
While it is probably true that a motivated criminal with the correct tools and knowledge can break into any network, this takes time and money, and why is this highly skilled criminal going to come after ME? Don't stand out, and you won't be a target. I'm not saying to use weak passwords, and turn off network encryption, etc.., but there are millions of wifi networks out there, skilled criminals go after high value targets... I really don't see what can be found on most home networks that is high value - you're going to go to all the effort to get a social security number, or steal my music or my pictures?
Do you have metal bars over all your windows? The best door lock in the world will not stop someone from breaking your window? Then again, it might motivate a criminal more if I had metal bars over my windows (especially if the neighbors don't) because I must have something of value to have spent this much on secuirty.
I guess my point is we can never be 100% secure. Therefore, lock your doors to keep out the hooligans, but I'm question the value of going much further... if somebody really wants to get in, they will.
Stan