I stamp images for cards, to colour in using Copic markers. I love Versafine ink the best for that, in black or sepia. It's more costly than some, but you get superb coverage even if your stamp is cheap and the image is intricate, and the black pad I got 4 years ago is still going strong. Ideal for greetings and sentiments too.
I tend to use my little coloured ink-pads for inking edges rather than stamping. I haven't found a good colour ink for stamping, although cards I have received from friends who have used Stampin' Up inks always look so clear and bright. I haven't managed to get Distress inks to give a clear image either, but they aren't really designed for that. The mottled look I get is perfect for the distressed look though!
If I have any problems with the colour running, I heat-set the image. Mostly I don't need to bother. I do leave it a few minutes to dry out properly before I colour though. I use plain old white office card.
I've seen Memento pads but only in one place here and they were $ . When I get back to the UK I may end up investing in those too.