HTML is Web. WPF is for native. I think Steve Ballmer said that and I agree with him.
I wouldn't want to touch HTML path IF it depends on IE. I am not dissing IE. The problem is, eventually the platform will stuck at an version of IE and never allowed to be upgraded, and upgrading IE raise potential risk of things starts to render in weird ways (Win7 Pre-RTM on Gadgets with higher DPI settings). And IE has higher risk of hardware acceleration fails (artifacts or crash) than native apps.
I go with web because you can use it everywhere. Apps are extra candies.