Several Tablet PC hardware announcements/leaks/what-have-you in the past couple of days:

Some pictures are out of what looks like a tablet from IBM (long rumored and IBM has told me when I speak to them that it's coming, just not commitments):
http://jkontherun.blogs.com/jkontherun/2005/04/fcc_pics_of_the.html

Hot new Toshiba M4 Tablet PC - looks very nice (but heavy):
http://www.toshibadirect.com/td/b2c/cmod.to?coid=-29325&ccid=1291041&rcid=-26367&seg=SMB

Funky low-power, long-battery Electrovaya Tablet PC (interesting one, but not a power notebook replacement):
http://www.electrovaya.com/product/sc2200WXA1.1.html

Another Toshiba, the R15 Tablet PC:
http://www.tabletpcreviewspot.com/default.asp?newsID=229

I'm still using an Acer C300-series. Still works, but I am holing out for the IBM to see what it looks like, since I am awfully impressed with their T-Series laptops.