Going from DX to FX - which lens Nikkor 24-120/4 or 24-70/2.8 or Tamron 24-70/2.8 VC

Maybe my best choice at the moment is to keep my D90 and get one of the lenses mentioned above and use it on DX for the time being?

I would however be reluctant to invest in DX glass as I am still aiming to go FX in the future!

The Nikkor 24-70 seems to be well regarded on DX as well.

At the moment I am a nit nervous about buying the Tamron as it seems there is still problems to be sorted out with  that lens.