Hi Bracken,
Most people start knitting on a 'standard gauge" machine; they are very versatile and can knit a very good range of yarns.
There are three main makes, Brother, Toyota and Silver Reed/Knitmaster. The only new ones being sold at the moment are Silver Reed. There are many second-hand machines available but rather than suggesting a particular make, I would advise you to look for one that is in really good condition, preferably one that has been serviced and has a new Needle-retaining Bar. The last thing you want to do is buy a machine that does not work properly and gives you problems before you begin. Make sure you get the Instruction Manual and check that all the original tools are present. There is a page or two in the manual which details what came with the machine when new. Whether you choose a punchcard model or an electronic is up to you; the basic techniques are the same on both. If possible have some lessons or do a correspondence course. Metropolitan Machine Knitting do a really good one for Japanese standard gauge machines.
Hope this helps a bit,
Sue.