Most of my polishes are Attitude (Star Nails). I bought them on B1B1F at Sally's but I have stuck with them so far because I do like them. Some of the darker colours can go a bit thick (although of the 40 ish colours I have, this only seems to have really happened with 'damson wine') but all in all they have worked very well for me and stayed on well. I also buy Nail Basix polishes from the US. They are 98 cents a bottle and seem to last OK, but be aware that what they show on screen is often not what they come out like. If you can I would always see a polish on (either with a tester or on a colour pops type display) before you buy, or see them in person at least, as screen or printed representations are usually quite poor and have left me disappointed in the past.
I am STILL searching for a brand that does a 'sherbet' range of colours (pastel pink, blue violet, yellow, green), the only ones I have seen this colour are the expensive polishes used with the Easy Nail Art kits. Likewise I have some 'commerical' nail polishes in my own collection (Rimmel, Miss Sporty etc) which I wish I could find in a professional range - things like more glittery colours, and Rimmel do a fab deep purple with turqouise glitter in it.....
I will possibly switch to a slightly more expensive brand in the future, but so far I have yet to find another brand which satisfies my rather picky nature about colours. I'm such a pain!!