level have been 0 day stuff or problems down to patch cycles. Things like you get a driver update that breaks some of your machines (seen that twice at home as well) bundled in with other fixes.
User education is another one, I still get emails from our IS department about not sending my bank account details to banks I don't have an account with.
Home wise most of my problems were pre XP and down to my son's inspired lack of technical knowledge and his habit of looking at naked ladies, getting free music, free ring tones etc. Not to mention freely accepting the largesse of anyone who chooses to IM him.
Just setting him up his own unprivileged user account solved most of them. AV and Tea timer along with a software firewall pretty much killed most of the problems. He uses IE and has the largest collection of unwanted toolbars in the known universe though. My AV regularly picks up bad guys in his IE cache that have been unable to self install, so I'm down to house keeping now.
Windows security has improved dramatically over the last few years, though personally I believe through design choices they've erred on the side of connectivity as opposed to security.
While nearly all prevention is effectively signature based, the security model is default allow and the lack of kernel and user space separation is still in operation we are going to have to be constantly vigilant though.
Most corporates lock down their users to avoid them shooting themselves and loads of other people in the foot. Some still don't though. Others still have exceptions.
I have admin rights on my PC and effective permission to go out of bounds of the default
company policy in order to do my job. So they are reliant on my knowledge, that's OK most of the time I do know my arse from my elbow.
Of course then you find out a manager who's regularly confused by the off button has the same access on account of he's a boss.
Ho Hum
It is getting better, and it can get better still, we need alternatives and we need to put the pressure on though. Securing software costs money and cuts into profits, so they won't do it unless they have to.