I have been interested in CSS frameworks recently and have played with 960.gs and BluePrint. Both are great and now I found the winner – a combination of the two and more – BlueTrip and I am using this for a lot of my projects including an earlier mockup of my site. I highly recommend it as a starting point for web developers/designers.
For those who are not familiar with the CSS frameworks, check out the link above and fascinate yourself with a lot of the groundwork already done for you. Another great feature of BluePrint is that it combines all the CSS files into a single file (unlike some of the other frameworks which have several files in an effort to keep the file size smaller) which will definitely help cut down the number of requests from the browser.