Love using illustrator CS for the inking stage. Illustrator gives you greater control for adjusting thickness of line and also maintaining the stroke weight through out the image.For the little alien dude I mostly used 1 pt stroke and to give the image a bit of punch I used a thick 8 pt stroke for the exterior outline.
I have often used Illustrator to do up the inking stage and then export or save out to Photoshop where I can then colour up to my little heart's content. It can be labour intensive using illustrator but the pay-off is having the yummy crisp even stroke.
