I'm going to be finishing my basement and needing to look at my current full 100A panel and expanding it. Currently has the following circuits:
20A kitchen
20A kitchen
40A range
20A water heater
15A basement lights
30A air cond
15A lights
15/15A furnace
15A lights
20A washing machine
30A dryer
60A garage
Isn't the garage breaker fairly large? There is a welder outlet on 30A breaker however it's currently not used. Just a gas furnace, door opener and outlets)

So with these 12 my panel is full and I'm considering adding a subpanel. I figure the basement lights cct I could put in the breaker to feed the subpanel so I could move all the basement lines to the subpanel.
However, I'm not familiar enough with what size of breaker I would need to run to the subpanel. The basement finish is going to have 2 BRs (1 legal/other using for storage/closet) a bath and a family/computer room.
For circuits I figured:
1 15A for BR1 outlets
1 15A for BR2 outlets
1 15A for BR1/BR2 lights
1 for bath (GFI... size? 20A?)
1 15A for FR lights
1 15A for FR outlets
1 15A dedicated for computer/theater equip

What size panel would I use for the sub and the breaker to feed it?

Thank you.