I recently went to AG so realistically you only need 2 pieces of equipment, the MLT and a good thermometer.
I made this, $80:
I bought 2 thermometers, one that Evan! recommended (pricey) and a $20 one at Target (you can find one comparable at Wal-Mart). The $20 is near as accurate, faster and has a timer. Both have magnets. I use both but like the Thermoworks one better but if on a budget, the $20 is great too.
You don't need a mill, get your grains crushed at the LHBS/Online retailer. If they don't crush, choose a different shop.
It took my 3rd try to get my temps correct. I batch sparge and on my 3rd attempt I batch sparged VERY SLOWLY and my effeciency jumped up.
I'm getting into the software, not required if you are given instructions but helps with understanding what is going on better so for your first batch or two use a recipe from this site the specifically says how much water and what temp to mash and sparge with. Ed Worts recipe's ring a bell.
Going AG will require full boils when considering the recipe's. If you have a 30qt you are fine. Basically I went AG for $100 and love it!
Here's some pics of my equip, 3rd batch of brewing AG: Picasa Web Albums - Mike - Double Simcoe...