I’ve upgraded QuickGraph to C# 3.0, and it’s extension methods and lambdas (requires .net 3.5). The result is fairly nice, specially the extension methods who make algorithms more discoverable.

For example, the following snippet shows how to get the topological sort of tables out of a DataSet (useful when you need to fill/delete tables):

I'm working with a customer that is implementing a website that allows customers to purchase products... This site has to talk to various webservices to obtain information about pricing and delivery options.

They were concerned that they didn't know what the interface for the delivery options web service was going to be so of course, I simply highlighted that this should be abstracted from their system as much as possible. All they new is that for a given order (made up of delivery address and the list of products) delivery options will vary depending on the types of products ordered and the delivery address. Other solutions (such as an internal call-centre package) will also be using the delivery options web service.