Concerning tax -
how will you state it? as bitcoins? you're changing enough to cover bills, and keeping the rest in bitcoins. Taxman phones you and asks where your money is, DON'T lie, be honest, you say "urm, I have spent all my (converted) cash, you can see my bank accounts, but I have bitcoins." They'll be like "eh, what?", they'll report it back, but there's nothing they can do unless they bring bitcoin into their system of tax (which would be amazingly awesome for bitcoin taking over the fiat, it would kind of be a tipping point, in the far future probably).
You don't understand. Let me explain.
You work all year long. Your employer pays you
only in gold coins (nuggets, bars, dust, whatever). You
never convert that gold to fiat in order to purchase a single thing.
You
still owe taxes on your earnings, and you owe it in
legal tender (fiat flavor of the land). If you don't file and pay, you are evading taxes and subject to punishment.
Replace gold with bitcoin and the story remains the
same.
Don't think for a second that the tax man is stupid enough to let a loophole like "being paid in something other than fiat" exist. They want your share, and they will get it.
Again, I'm telling you this not because I agree with it, but for your own well being. Evading taxes is going up against the guys who have a monopoly on aggression, be safe.