A tablet is a tablet, and a PC is a PC. So a "tablet PC" is a bit of a misnomer.
Do you mean a tablet like an iPad or Samsung Galaxy Tablet?
If so then they are the best two tablets on the market, but they are the most expensive. Both are available around 10" screen size.
You say price is a factor, so how much are you willing to spend?
With tablets (like most things) you really get what you pay for. Better screens, better cpu, more memory, more reliable etc.
You can buy a 7" as they are cheaper, but you do of course get a smaller screen size. The Google Nexus has just come out, a 7" tablet.