Depending on the size of your target market you need to take a high-volume, low-touch, or a low-volume, low-touch approach.
If you’re aiming at the enterprise space, say your target market is fewer than 10K businesses, then you don’t need lead prioritisation tools because you already know who your potential purchasers are at the company level. You could call them all in a week with a small team of salespeople. You need a brilliantly targeted content/inbound strategy, highly targeted approaches using LinkedIn, Events, Rapportive, Prophet, etc and above all a big network (buy lots of coffees and lunches). Your challenge is knowing who WITHIN your target prospects is the right person, and what will push their personal buttons.
If you’re aiming at mass market (>10K market size is my rule of thumb), then you can’t rely on teams of people to do your lead filtering. You need a brilliantly-targeted content/inbound strategy (again), then a smart way of knowing your total universe of prospects and who to contact first.
A traditional approach is to buy data from DnB, Experian, BvD, Hoovers, Data.com, Avention etc. These will allow you to target by SIC code, geo, revenue and many other filters.
A more contemporary approach is to go to a Marketing Intelligence company like Leadspace, Radius, Everstring or Growth Intelligence (my company). They will learn as you reach out to companies and get better at predicting who will respond positively over time using a broader array of ‘un-structured’ data.
Once you have a working hypothesis of your targets from one of these sources, test and learn! Bear in mind that no outbound strategy is efficient without a good content/inbound strategy . Email marketing has traditionally been recognised as the cheapest way of generating a marketing qualified lead, telemarketing can work very well (nothing replaces a human – human outreach sometimes), online advertising has not traditionally been targeted enough for B2B although this is changing with solutions like Demandbase allowing targeting by IP Range.
As ever in life, a sensible mixed strategy gives you the best chance of predictably hitting your targets.
A link to the Quora page: http://www.quora.com/What-are-the-best-tools-and-services-for-generating-high-quality-B2B-sales-leads