As far as contact managing goes, Outlook has a contact manager, and although it doesn't call it a "Real Estate Contact Management System", it still holds contact extremely well and efficiently along with calander, all that other stuff, etc...
We use Outlook to manage contacts where I work, and it has not failed us yet. As far as a seperate tool to the job, as well as doing CMAs and a whole lot of other stuff (including a really cool HTML-based satelite imagery feature), you may want to look into joining the Site To Do Business, from CCIM. It is at
http://www.stdbonline.com.