Like you, I use Windows on my home desktop, my laptop and at work. I used PPC's too, until getting my 650 late last year. The 700p is my 2nd palm device. I have no problems whatsoever. I've sync'ed with my desktop and laptop and I use Outlook for my home email and contacts, etc. There's no problem between Palm on the Treo and Windows on everything else.
As for the rumored 750 on Cingular, here's a
thread for the rumor folks. You can probably find all kinds of others floating around the net, too.