I would like to know how long you keep your nails for those working cards? I need to find a length that still allows me to look professional, yet still be able to manipulate cards. Any help would be appreciated.

Normal.
about one milimeter of white nail (if that makes any sense), but I also play guitar.
Make sure they are clean and well groomed. That is more important.

Mine are about the same, make sure not to bite them. Your hands are oftentimes the focus of a lot of attention. If you ever watch the bill Malone videos he looks like hes a nail biter. He has hang nails and such on his fingers and it looks rather nasty. If you watch some of the Sankey videos though, his hands look like they were professionally manicured, which my girlfriend says looks funny, but I think that would do as well. I agree with abc, clean and well groomed.

As far as the clean and groomed, that isn't an issue. I take pride in how my hands and nails look. ABC, thanks for the tip.