I don't think it's possible to say for certain, because there are too many factors involved. Here's my mostly uneducated opinion on it though: we're seeing huge valuations and investor commitment in startups while at the same time seeing big co's throwing lots of money at each-other in lawsuits of various kinds. I think these are two symptoms of the same problem: that the consumer market is still stagnant, and will be for a while. Well, that coupled with commodities speculation and other unstable markets.
From an investor standpoint, I think startups are where the smart money is, if you have enough cash to play the game. So, of course capital is going to gather there, and it's going to keep doing it as long as it's the best place to put a few million dollars if you want to make a few million more.
So how long will it last? I think it'll last a while -- until the consumer markets start to improve and other investment strategies become stable again, and there are enough Groupons to seriously hurt the perception of the startup investment strategy.
There's no sign so far of real improvement elsewhere, and right now only the crazy people are the ones saying that startups look like a bubble. So, I'm guessing this will go on for at least a year or two.
Purely from a business standpoint, if you can get access to any of this capital, and if you're willing to play the game and give up some amount of control over your business, then you'd be foolish not to take the money. If nothing else, it might give you a tremendous edge over your competitors.
However, there are no free rides. The capital could come with a big risk: that when the market finally corrects again, your business has been spending beyond its revenues for a couple of years and the adjustment is so painful that it kills your business.
I think this really comes down to how you think; if you think in terms of, "what do I want to be doing in three years", then you should probably take the money and get rich and have a good time, and if the business collapses afterward, who cares? But, if you think in terms of, "what do I want to be doing in thirty years", and if your business is important to you -- then maybe still take some money, but be more conservative about it and make sure you can survive once everybody decides that startups are a bad investment again.
But I really don't know what I'm talking about, and I bet a bunch of folks are about to turn up and tell me so. :-)