The x61 is going to be the most powerful of the lot, but that is also what is going to make it lack in battery life compared to the other two, since it sports a low voltage processor and the other two sport ultra low voltage processors.
That said if you are always near to an outlet, or plan to buy supplemental batteries that will be less of an issue.
I have seen some negative reports on the fujitsu model & hp model, some users appear to have erratic trackpoint drift: http://forum.tabletpcreview.com/showthread.php?t=13413 , and the hp model, seems to have stripping of the wrist area of the tablet: http://www.gottabemobile.com/forum/f...s.asp?TID=4926, honestly the latter is why i chose to buy the x61, i was tired of all these shiny notebooks, that w/in a couple weeks to months of ownership, started looking old & tarnished.
I've found the build of my x61 to be sturdy, and they definitely have the best trackpoint in the business. I was afraid of the trackpoint, having used them on toshiba's & dells & finding them impossible to use, but i've actually gotten to the point & we're talking w/in days that i find it easier to use than some trackpads...go figure (and can't let my cousin hear me say this)
The x61 also has the option of the sxga, so you'll have pretty good screen real estate.
gottabemobile has comparison video of the two models you're trying to rule out here: http://www.gottabemobile.com/Fujitsu...deoReview.aspx