In order from thumb to little finger on my right hand:

• potable room temperature water (always have fresh clean water to drink!)
• potable boiling water (no more waiting or using energy for kettles and so on)
• coca cola from a room temperature can (my favourite beverage and way to drink it, on the middle finger because it's sticking a middle finger up to the coca cola corporation by getting it for free)
• helium (gases are fluids too! help solve any helium shortages and also gain access to a cool party trick [squeaky voice on demand] ring finger because I don't see myself using this one all that often and that's the most uncomfortable one to use)
• acrylic paint thinning medium (sounds like a good idea but I've only ever used water, would like to experiment with it but it's expensive and I could just get new colours for the money)