4x10. I discovered the Marshall 4x10 guitar cabs a couple decades ago, fell in love with their compact nature and huge, tight sound and never looked back. That led to being willing to try out a Bassman combo, and guess what - love it. The Bassman has become my main gig amp now.
I have 8 2x cabs - 3 10", 4 12" and one 15". The 15" is a Dual Showman cab with JBLs in it. It stays in the practice room and serves as a bass amp. The 10's are all closed back, Fender Tremolux style cabs. I love the sweet punchy sound and easy portability. Two of the twelves are Marshall style - a 1936 side by side and a 2061 diagonal slant. The other two are Bandmaster/Bassman small cabs.
I also have a 1x10" sitting in the living room for playing by the tv and a 4x12 Marshall 1960a that never leaves the practice room. Too big.