In reply to Tree: I made the jump five years ago... it's great working for yourself - no stupid bosses whinging at you all day, although stupid clients make up for that! You will end up working long hours, going stir crazy sometimes through lack of human contact. Having noone to bounce ideas off takes some getting used to too. However, you can take time out when you want to, and not feel guilty if you're late into the office! Be aware of the amount of outgoings you're now going to have to cover - personal and business. Such as upgrading your Mac every three years or so, buying new software, keeping a buffer to pay print bills when the client is late coughing up for their invoice, plus giving yourself a salary every month. It' takes some time to build momentum.
Apart from all that, enjoy it and try not to get too stressed.
C-: