A 100-amp service is about the minimum acceptable for a house nowadays. 150 or 200 amp, even 300 amp, are much better. And if you have any choice about it (like buying before the house is built), go for the bigger service. It really only costs a few hundred $'s more to go for 200 or 300 amp instead of 100 amp when the house is being built. It will cost you many times that to convert at a later time.
My advice is to always over-do electrical stuff. It ends up being useful in the long run.
As for “crappy” aluminum wire, it’s not really that ‘crappy’. The problem is having a mix or aluminum & copper wire, and not doing the connections right. A lot of older homes had aluminum service coming into the house – that’s fine if it’s done right. (And since you are hiring pro’s to do the wiring, it should be OK.)
But really, there is not much point to aluminum wire any more. It used to be much cheaper than copper wire, now the difference is pretty slight. So go for all copper if you can.
I’ve heard that the price drop on copper came about the time the Bell System/Western Electric discovered recycling. They added a box in each of their green trucks for recycled scraps of wire, and at their factories. This ended up becoming the largest copper mine in the world – that is, the amount of copper they recycled was more than that produced at the largest copper mine.