Yeah, it totally depends on your niche and the competitors you have to deal with.
However I will say that one way that I like to go when I'm getting frustrated about traffic is to go after product specific keyphrases only and build tiny domains around them. Then you know that any traffic you DO get is super targeted - they're already in buying mode.
Right now I have a tiny little site - ten pages - launched in October. Haven't done anything with it except for the first week I built about 50 backlinks. I'm getting Valentine's day related traffic right now and averaging two sales for $20 commission each from just ONE visitor. Nice! So you need to also try to get extremely targeted traffic, that ends up being more important than huge numbers. If it's tiny traffic but it converts super well you'll be very happy!