Ask HN: Best CRM solution for bootstrapped startup?

i'm long overdue to adopt a program, but now that our b2c startup is entering the b2b market, it's definitely time.

here are the three biggest things i'm looking for:

-notifications when to followup with certain people -notifications if contact never responded to email (does any service offer this??) -a system that organizes my contacts by priority ( i currently http://gist.com to put my contacts in perspective, but it's just a reference -- not actionable for me)

i'm looking for a free service at this point to use between two of us -- any suggestions?

what is your CRM of choice? specifically, what makes it great? thanks!

-adam