This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
In the real world we always build a prototype of what the application will look like first, so I would think that you should build the client side first. Of course, I didn't do it this way. I got so caught up in reading some of the discussions here on locking/unlocking and making the database accessible to multiple remote clients that I couldn't resist jumping in and building my server first.