There are two milestones in the near future.
The Macworld iWorld, which apple does not participates but speculation of some
unofficial official announcement (well Apple is like that

/ Jan 26th) and the World Mobile Congress (Late Feb 28ish~3/1 IIRC).
Therefore I would personally not chose to purchase anything at this time.
With that said, now-a-days tablets are pretty cheap (compared to what laptops costed only several years ago), so if you need one, go for one.