Just went through this. From memory:
Water pump.
T-stat.
Coolant.
Spark plugs.
Oil w/ filter.
There are 2 overhaul gasket kits. They are very close in price, but if your lower end isn't leaking you could opt for the less expensive one.
There were some other minor items that I can't recall. Like bolt, nut, etc.
When you get the heads off you'd want to check everything for flatness. Unless the vehicle over headed you most likely won't have to have the head machined. I didn't. I'd replace the valve stem seals as they come in the overhaul gasket kit. Ideally I'd perform a leak down test with everything still intact to make sure the valve seats are still good. All my cylinders checked out good. It'd be very unlikely that the valve guides would need replaced.
Assuming this is an even cylinder? Mine was. I had the fuel injector for the cylinder with the leak put on the other bank. That way if it every gave me any issues, it'd be a lot easier to replace. You could send it to be cleaned and flow tested. I'm the type of person that likes to understand the reason for a failure so it doesn't occur again. However, with this failure the general consensus is that the original head gasket is inferior and the main factor that led to such a premature failure; thus Toyota re-designing it.
Sometimes the chain tensioner needs replaced. Most see this around 150,000 miles. Mine checked out fine with 130,000.
