We are a web based company and our mix includes: zendesk, get satisfaction, github, campaign monitor, new relic.<p>Also - many small businesses pay for ours -<a href="http://www.pipejump.com" rel="nofollow">http://www.pipejump.com</a> (:
Basecamp, Dropbox, Highrise, Campaign Monitor, Xero, probably a few more.<p>(That's my company, not me personally, personally I don't have any paid apps. I've no problem with doing so, just never needed any)