I am looking for a good b2b traffic source. My offer is in the financial space. I am just looking to generate leads no sales.
Try LinkedIn - they have self-serve ads.
xing and linkedin would be my first choice as well 
thanks
business.com maybe??
Google adwords, linkedin, GCN and even FB can be effective places to buy ads, but what matters the most is how you setup the campaign, how you target your ads, etc.
That being said if you want to talk about the offer PM me, I run an ad agency and have worked with quite a few B2B clients...
Bizo.com for b2b ads. You can also use reply.com.