I'm a hardcore advocate of the indubitably awesome UCCW, but Zooper is a very strong contender in the widget-making arena—it's (arguably?) more powerful. If you want full functionality (eg. tap actions) you'd have to get Zooper Pro, though.
Totally customisable widgets. Make them yourself or use templates with this free version or download others in the paid version! It also integrates very well with Tasker to help you control what data is displayed.