Sinks seems to be a plus, but it is all about design. A well designed bathroom with only one sink is just as great as an equally well designed room with two sinks. But an unassuming bathroom with one sink seems inferior to an unassuming bathroom with two sinks.

As far as the tub goes, it's only really important that there is at least one tub in the house, so if have another, then it's just preference. That said, having the right tub can really add to the design if done correctly.

To me, what is important is having a bathroom that is comfortable, well designed, and with some natural light if possible.

If you really want confidence that your money spent will look good in the end, get a bathroom designer, good design is worth it and it'll take care of a lot of the whatif's.

Also, don't skimp on the toilet! A good adult height toilet with a strong flush is worth it's price.