My expectation about a counter offer is, they just need to keep you until they can find a replacement for you.
That said it all depends on your reasons for leaving. If it is environment only, then definitely no. If it is more money maybe, but expect to be high on the layoff list should the economy turn.
It was in a very hot market (hot specialty at the time in Eastern Europe, where there's a ton of hiring pretty much no firing yet - we're the destination where a lot of the outsourced work from Western Europe and the US ends up in). So, they didn't retain me with counteroffer only because I had specific project knowledge, but also because realistically hiring a replacement would be a pain.
