Macintosh

MacBook Air was released by Apple. I am using PowerMacintosh 9500 with 500 MHz XLR8 G3 card yet. I fully extended this computer with expansion cards, such as rage 128 graphic card, ultraSCSI card, and 100baseT LAN card, and storage devices. I used it for a decade. But it runs only old OS9, and OSX is out of support. I installed OSX by using XPostFacto but it was not usable at all. I have always wanted to buy a new computer.
I want a laptop for my presentation, but do not like to work on it. I intend to use it with external monitor and keyboard, so I am afraid that the MacBook air is not in my option due to the limited expandability. I expect to buy a black MacBook. But I hesitate to do that, because software cost as much as the computer itself. Most applications I have are only for old systems. Can I run the Office for Windows on OSX by using Parallels Desktop or VMware Fusion? And more important, SheepShaver is workable for using my old CricketGraph data files? I have many concerns about buying a new Macintosh.
I have old Macintosh IIci and PowerBook 180c too, but they cannot boot up now. Their hard disks seem to be dead, but I have no plan to repair them.