I see this question all too frequently on the Microsoft TabletPC newsgroup and the answer is always the same. The Windows XP TabletPC Edition is a superset of Windows XP Professional; what runs on your average laptop should run on a TabletPC. There might be a few exceptions, due to the fact that the additional Tablet components might, as with any other program or driver, have a conflict with something else that is installed on the system, but there have been relatively few reports of such exceptions. I, myself, cannot run Farstone's VirtualDrive without experiencing constant Blue Screens of Death, but I've read that other tablet owners do use this excellent tool with no issues.
In my experience, no few application compatibility issues stem from using the computer manufacturer's original image (with all its extra bells and whistles), which is why a lot of people prefer to take a new machine out of the box and install a nice, clean version of the Operating System (OS). With a TabletPC, one almost certainly must use the manufacturer's image or risk losing the functionality that makes a TabletPC more than just another laptop.
Your high-end, graphics-intensive 3D games are not necessarily going to run, either; for the most part, TabletPC manufacturers are not yet catering to the needs of gamers (but perhaps Microsoft’s game SDK will change that), so the video cards installed in TabletPCs aren't always up to the challenges. I found that Warhammer 40K: Dawn of War wouldn’t run unless I used the game’s safe mode (while my V1250’s integrated Intel graphics card can access up to 64mb of the system RAM, it has no T & L support; still, it handled itself well, even in 8-player LAN games at 1024 x 768 res). Games that will run on TabletPCs often cannot handle the input coming from the pen, which sends a lot more coordinate info to the OS than a mouse does, but slates can accept external keyboards and mice, and convertibles already come with peripherals that games can understand.
I always wondered why people kept asking what seems like the obvious to me, and after answering “no,” for the umpteenth time to someone asking if my computer was a giant PDA or “Palm Pilot,” I finally got it: until this form factor really takes off, people are always going to mistake any flat computer with a pointy-stick input device for a handheld, and lots of people know by now that you can’t run just any old app on one of those. That is why this blog entry exists, in the hopes that some will read it and be made aware that a TabletPC is a fully-functioning, fully capable computer, and that it will very likely be able to run whatever Windows XP-compatible application you desire, and then some.