Recently I have spent quite some time measuring and tuning the performance of the Imtech SharePoint Enhancement Toolkit: a toolkit that I have built in order to achieve standards compliancy, accessibility and slightly more performance of SharePoint Web Content Management (WCM) solutions.
Content Query Web Part (CQWP) is probably the best solution for data aggregation within SharePoint 2007 solutions. The limited functionality exposed through the standard UI is compensated by caching and high performance of the CQWP. Yet there is one thing that can keep you off using the CQWP in environments which require you to deploy your solutions including the configuration in a fully structured and repeatable manner.
Lookup Fields as we know them
I create very often little projects to try things out: either based on the Console Application or the Class Library template. As it's SharePoint development we're speaking of the first thing you need to do is to add references to the Microsoft.SharePoint assembly. Depending on what you're doing you might need to add the references to System.Web and Microsoft.SharePoint.Publishing as well or maybe even more. You can do it just the regular way by clicking with right button on the project References and adding new reference but there is a faster way.
Recently, while researching the RSS Feed mechanism of the Content Query Web Part I have stumbled upon the SuppressWebPartChrome Property. As this Property sounds very promising but is not very well documented in the current WSS SDK I have decided to have a further look at it.