By John Tozzi, Stacy Perman, and Nick Leiber

While 2008 was clearly an awful year for business, a look back shows entrepreneurs running startups managed to raise significant amounts of capital to fund their plans for growth. In fact, venture capitalists invested more than $7 billion in seed and early-stage companies in the past four quarters — more than any calendar year since the dot-com bubble burst in 2001.

With this in mind, BusinessWeek set out to find the hottest new businesses across the U.S., based on the collective judgment of the venture capital community. To do so, we followed the money, looking at deals that took place in the four most recent quarters available, from October 2007 to September 2008, based on the MoneyTree Report from the National Venture Capital Association and PricewaterhouseCoopers. We then reached out to a selection of the seed and early-stage companies that raised the most money. For profiles of 25 of these startups, click on. Then weigh in on how you measure a startup's potential for success in this post on our staff blog.