Depends on several questions, most (if not all) related to you.
- What do you need and/or want in a new camera?
- Does the current version camera have all of that?
If it does:
- Do you have the money to buy it? (If not, then you'll have to wait regardless, and ask yourself this question again later.)
If it doesn't:
- Can you afford to wait for this functionality for an unknown period of time, without any upgrade at all?
To help specify this decision, keep the time scale of new products in mind. Rumours can come and pass without any actual updates. Announcements made by Canon indicate that it will arrive, but usually it is a couple of months before it actually hits the markets, and another 2-3 months before the price drops enough and it's actually available in stores. On top of that, for the 70D specifically, it's more than likely that a 7D-line upgrade will have to come first (or at the same time). Currently, even rumor-wise, there isn't much of anything about a 70D yet. It might take a while.
For me personally, as I'm also considering the 60D or 'waiting for an upgrade'...
- What do I need in an upgrade?
I want an ISO upgrade to my current 1600 max (EOS 350D), increased burst rate, increased resolution (8Mpx currently), better AF, video recording and perhaps weathersealing.
- Does the current version camera have all of that?
The current 60D has all of that. Of course, 6400 ISO (although it is a full 2 stop ISO increase) starts to look a bit unimpressive compared to the new full frame flagship (1D X) that goes up to 51200 native ISO. Considering sensor upgrades in the next version, it's more than likely that a 70D upgrade would offer an even bigger ISO upgrade.
But I shouldn't let this "extra ISO upgrade that might be incoming" stop me from buying a 60D. A 2 stops ISO increase is a large upgrade. If I wait for the 70D, the upgrade might be 3 or 4 stops in ISO performance, but waiting for it would mean not having any upgrade on all those points (ISO, resolution, AF, video, etc.), for probably well over half a year. In my case, it's pretty clear: I can't afford waiting an unknown period of time.
And if after a year the 70D is in stores, I can consider selling my 60D body with still 1 year warranty on it for a 70D if it really is that much better. I'd lose a little bit of money in the process, but that's 1 year with a very big upgrade that was well worth paying for.