I'm partial to Shimano. Everyone loves the Curado, but ever since they released the Citica in three different gear ratio options, I have found them to be a good option even in comparison to the older model Citicas that were already great.
Edit: The Citica can be found for ~$120 new, while the Curado are around ~$170 new. I'm sure you could find better deals than this, but just thought I would throw it out there for price comparison purposes.