I've been getting into WPF more and more lately. It is a lot of fun and once the tooling really catches up and there are more example apps and tutorials, I think the learning curve will drop a lot. One of the big complaints I hear is the WPF does not ship with a datagrid. There are a couple of third party options, but now that I have started to actuall build some stuff with WPF, I think you have to really step back and see if you really need a datagrid.

The datagrid makes it easy to lay out data, especially in the layout challenged world of WinForms (as compared to WPF at least). Using nothing but a simple listbox, you can do some wonderful things as far as data display. For a lot of scenarios, this easily replaces what you were using the datagrid for. With a touch more work, you can easily add some sorting and filtering capabilities as well.

If you need advanced mult-column sorting or filtering, inline data editing, etc. then maybe you do need one of the 3rd party grids. But if you need to do basic display/sorting/filtering/etc., WPF gives you all the tools.