SPFarm objects represent the highest level in the SharePoint hierarchy as they represent the entire SharePoint farm. SPSite objects represent site collections, which are the largest objects users typically interact with. SPWeb objects represent individual websites within a site collection and contain things like actual content. Visual Web Part projects include a default user control and preconfigured web part to load the control, Sequential workflows have a defined start and end while State Machine workflows allow items to move between states without a predefined order.