I have a love for DARK nail polishes, I like for my nail polish to stand out and make a statement. My most recent newbie is OPI's Espresso Your Style that a received on my birthday, thanks J! I love this color, it's a rich brown with a light hint of sparkles which adds a nice shimmer. I just painted my toes with it and they look great with my Steve Madden sandals.
Recently, I also bought some cheap-o nail polish (LA Colors) from Five Below, 3 for $5, I just couldn't pass up the deal :) I have to say that the polish isn't as bad as I thought it would be. The polish hasn't chipped and it goes on pretty smoothly. Five Below also has nail art paints which are pretty expensive at the beauty stores but only $2 here. I just used it on my neice's to make little flowers and hearts on their toes and they loved it! The nail art paints are a bit stringy when you use them so you need to be careful not to mess up your design when using them.
I have a preference for OPI and China Glaze nail polishes but I think Sally Hansen makes a pretty good cheap alternative. You can also find OPI nail polishes at better prices online, check out Nail Polish Diva.