"A good marketer can make more money from a 2,000 subscriber list than a bad marketer to a 100,000 list." ... I've seen a merchant with 9000 (approx) on her list make $17,000 for the exact same offer that a "big name" marketer with 60,000 on his list made $800 for and (this one's fun), another "big name" marketer who claimed 125,000 on their list and made $2200 with.
9000 = $17,000
60,000 = $800
125,000 = $2200
These are real numbers (well, the revenues are... the list size is just from conversations of what those affiliates stated that they mailed to).
So I agree and I often harp on the fact that the database size isn't relevant. It's the quality of the relationship with those leads.
As Ken just suggested, please think bigger. Many will stop at "how do I get a lot of people onto my list" and, in reality, the money is in "how do I get people on my list to know me, love me and trust me".
And while this is somewhat self-serving, I have some conversion info in my I QUIT report (that recently went live)... it's direct download / no opt-in so no worries... but I recommend read pages 47 to 57. :-D