a leak down test beats a compression test, if possible, but both are helpful for different things.
In any case, if it is just a leaky head gasket, if you can do valve clearances, you can do a head gasket swap.
side note: I had the same problem as Jay + others. My "leak" was a sunken cylinder that allowed both coolant into the cylinder AND for excess pressure to go into the cooling system over pressurizing it.
