I have a similar story as Splinter, I made the poker site, and forgot about it, then got a check.
Then because of other things in life I didn’t make too much effort with that site. Still, checks were rolling in (new affs: this doesn’t mean you just have to sit back and watch those checks rolling in lol, it was only a luck that I got some high rollers 
)
And this year I came back to these forums, tried out bingo, and fell in love with the game 
And I thought: why not, let’s make a site dedicated to this niche. I found this niche much more rewarding, as I can see my stats, the signups, it was much easier to start out than it was with poker, I think because of less competitor and because bingo is treated as a soft gambling product, lots of blogger friends I have from the women’s interests niche are willing to link to me without any nightmare. So I could see the results sooner, and it made me uber motivated 
So if you are someone like me, who want a prompt result on their investment (or at least you know that you can be demotivated with too much waiting), I can only suggest to start with a small niche, and forget about “online casino” “online poker” and such terms.
(Yvette, I’m planning to implement some recipes from time to time on my blog, would you be up for some guest-blogging?