First, I would evaluate whether a web client (ideally MVC+jQuery) can’t do the job…
Assuming a full client is warranted:
If it is a business app that demands a client, I would tend to go with the full framework and ClickOnce; the main difference here (re deployment) is that the client must have the framework installed – but past that, ClickOnce deployment is very pain free. Actually, building a ClickOnce manifest is much easier than Silverlight etc, since the IDE will do almost all of it for you; you just have to host the files somewhere (could be a web URL; could be a network UNC).
This gives you much more control (and power) at the client, as well as a far greater range of existing resources to use (for example, if you need, you can use some legacy winform code on the WPF surface). The “requires full framework” is also one of the largest benefits: “has full framework”.
You should also perhaps consider the 3.5 “client profile” setup; not sure how wide-spread this is in reality… but worth knowing about.