My personal checklist:
- no bigger than 11.6"
- pen input
- detachable keyboard dock
- reasonable battery life (ok if this comes from the keyboard dock)
- can run TF2 and older Total War games (Medieval II would do) at playable FPS. Eye candy not a concern
If the Atom machines can manage the games then maybe the ATIV Smart PC or Asus VivoTab. If not, I might wait on Surface - Microsoft have clearly given consideration to portability, using a 10.6" screen rather than 11.6", and going with a keyboard cover rather than a dock (the cover will be a lot thinner, so you're likely to keep it with you all the time). I'll probably need the extra few months to save up the extra pennies anyway.