1. the plastic setups are not only great for beginners, but for any AG brewer. don't get hypnotized by the bling (i know, i know, do as i say, not as i do
2. beersmith or many other programs (brew calculus, beer math, etc) make a *huuge* difference.
3. software + a calibrated thermometer (ice water registers 32F, boiling water registers 100F
--and yes, check them, many thermometers are off) will prevent 90%+ of all problems.
4. before you get into step mashes, really, truly understand why you would need one. again, 90%+ of the beer most people want to brew do not require a step mash. if you want to brew an award winning wheat beer, okay then it's a damn useful thing to do, but almost every other style you can cheat and do a single temp. oh, and i don't step my wheat beers either
as an aside, i used a plastic setup for ten years, until they died on me and i got some good deals on stainless. in all honesty, the coolers held their temps better (until i insulated the stainless with reflectix). plus, if you like to do, say, barley wines, you can get *enormous* coolers that can hold gigantic quantities of grain. my 15 gallon mash tun struggles to hold enough grain for a real barley wine or wee heavy, and i've been contemplating getting a cooler just for those really big beers.