Did you pick CentOS for a reason?
I ask because, if I remember correctly (and I used this distribution briefly), it is essentially redhat linux enterprise edition, but forked and updated from that distribution (to provide a free version of it). You probably would only want this distribution for something you need a stable server for.
As a desktop linux environment, I would highly recommend Ubuntu... things just tend to work on it (for the most part), and there is a highly active community with many forums you can search for problems on it.
I have set up 3 laptops and 1 server on Ubuntu, 2 laptops had issues but were resolvable via googling for forum responses, another high end laptop had no issues, and the "server" was a home server and was kind of old with pretty bland hardware, so no issues there.
At work, I am using Ubuntu with dual monitors and it works just fine, I don't think with any special configuration.
I know this doesn't really answer your question, but if you are using dual monitors it seems to indicate to me that CentOS might have been a somewhat suboptimal distribution selection. For cutting edge support on the RedHat distribution suite, you might consider Fedora, which is where they put all the newest stuff (which is more likely to support things like newer hardware)... but again, I think Ubuntu is a distribution you should consider.