I'm a huge fan of dark polish, but only on shortish, well groomed nails.
My tip to avoid yellow nails is to get a really good basecoat - I'm currently using one from Tesco (a big supermarket chain in the UK & Ireland) called
Goodbye Yellow
And my fave dark polish is also from Tesco & it's called Velvet - a really dark burgundy that is chip resistant for 5 whole days, even though I forgot to put an extra top coat on