Everyone has their own opinion - but the people with worthless opinions are those who are compromised, their identities stolen, their credit cards and/or debit cards compromised, and their bank accounts cleaned out.
My computer is compromised. Probably severely compromised. I take bare minimum precautions (as in no IE and knowing what sites are fishy). I've gotten 2 viruses that I've noticed. One removed safemade and did other fun things. Got rid of it in about 30m. The other I'm not sure what it's doing, I think it's a key-logger. I'm pretty sure I have some sort of bot that likes using my internet when I'm idle too. Probably a host of other bs that's not noticeable as well.
I also pretty sure my opinion is worthwhile. You see, I just don't do anything involving money on this machine. Setting up a machine to be secure enough to trust banking and credit cards is time consuming, annoying, and all around makes using the internet a trying experience.
So I just have a cheap old desktop to buy things and do banking on (or, actually not do banking on since I don't need to, but if I did...). It does nothing on the internet but update software and buy things from trusted sites.
The only significant risk I'm taking is email. Someone might compromise my account. I accept that risk for the ability to use the internet without having to deal with all the trouble of securing my machine.