Bella Mani is all part of United Beauty if i'm not mistaken, which is also to do with Star Nails. They have a nail varnish range called Attitude. I personally love their colours and they do go on very well, last well and have a good range of colours.
I also like the creative colours too so would recommend those as well, they have a very good range as Gigi said.
Its always good to look around to see what you like personally, but i do like my "Attitude" polishes alot so give them a go if you wish and see what you think.
i like opi nail enamels there are lots to choose from and don't chip, i have been lucky and picked them up cheaply from e- bay, they are a bit more expensive, but i believe you get what you pay for. i have heard that creative and jessica are a popular enamel (based on what i've come across in salons)