I always paint my bases last. I don't remember how or when I learned to do it like that, but I've always done it that way. Until now. I thought I'd try painting my base first to see what happens.
It always seemed like I had problems trying to get my base painted right around my model's feet. I couldn't get the paint in there on the textured base without getting it all over the model's foot. That or I had to leave a ring around his foot since I was too afraid to get close with my base color. Both results were not what I was looking for.
I thought if I could get the base painted first, it might be easier to paint the armour on the model's foot than it would be to do the base around it. Kind of like painting the recessed areas first and then the raised portions last when you could still get to them easily enough.
Turns out to be a pretty good idea. The only drawback now is that I have to be careful when painting the armour near the base so I don't get any paint on it, but that's the trade off I suppose.
Will it work for every model? I don't know, but I am going to try it a few more times to see how it works out.
Make sure to check out these posts as they might help:
Assembly: Standing on top of the base and not sinking in
How to hold your model while you paint it