Don't forget to get some decent speakers!

Mackie HR624s or 824s are the pick of the bunch without spending mega money; skimp on the speakers and you'll struggle to get it to sound perfect.

Also decent convertors help with monitoring ... never work off a soundblaster or some cheap sound card. You don't need to spend much mind you I've got the audiophile something or the other that Emotion mentioned that cost me 120 quid and sounds pretty close to the PT HD rig under all but the most intense scruteny (sp?).

PC with Cubase or Mac with Logic Audio seem to be the options. I'm a Mac/logic fan myself but oads of people here use Cubase. If you can get a supported one with it already installed and the soundcard installed you can save yourself a lot of headaches that get in the way of producing music. Carillion as mentioned are the top of the range for PCs in studios as far as I can tell, also worth mentioning are the ones made by Digital Village and Millenium.