I find that it's not so much the product used, but the technique with which I apply it. I'm using the double-ended black/white Maybelline one at the moment, but the thing which makes it work is that I use an old mascara wand (cleaned and dry, of course) to comb through the lashes and remove any clumps after I've applied the product.
I love the products Bourjois and Yves Rocher offer. They are wonderful, not tested on animals and the colours are really long lasting!
I love Maybelline's. Simply gorgeous.
Looks great. Doesn't clump, doesn't run. Water-resistant but comes off easily with any good face cleanser.
I prefer The Body Shop mascara, it plumps the eyelashes but it does cost a lot. I also like BodyCare mascara, cheap and does its job!