I use a 10ml, for Rodinal and alt processes, a 50ml that doesn't get much use since I got the 10ml, and a 250ml, used mostly for diluting liquid concentrates. Measuring cups work fine for most other things (4c/1qt/1l), and they have the advantage of doubling as beakers to mix dry chemicals. Even better, they are cheap! (I picked several up at a dollar store).