I tell you what: I would buy an UMPC immediately, if and only if they find a way to increase battery life. The current LCD technology used (CCFL I think) really eats from the battery - and with 1.5 hours or so, the UMPC fails in its original purpose - to be truly mobile.
Also see JK's comment:
http://jkontherun.blogs.com/jkonther...attery_li.html