For me it is not possible to answer this - every day different answer (I did ask myself this question many times).
Every time when I am going on some trip - I look on my 35mm cameras (nikon F3, FG, F801s, leica minilux, yashica lynx 14, yashica ME, minolta himatic F) and think: which two to take this time?
My favorite couple is F3 with 50mm and FG with 105mm when I am going somewhere (because I feel like armed with good weapons), for everyday use I like leica minilux with 40mm/2.4 (small and very very good).

But one day - just some M body with 50mm Summicron and minilux as spare camera