Thoughts on grad school? (CS PhD)
jmount: Given my experience (CS PhD. CMU) I would say that you are likely a very good candidate.  The PhD you left was pure-math (not CS) so I don't think it counts much against you.  You have lots of plusses (analytic and work experience) and the best thing would be to be very articulate about what you want to do (at this point they will be expecting you have some goals).  The CS GRE really can not be taken without some studying (it had some obscure stuff on it when I took it).Now for picking a grad school a lot of things are really important.
1) Will they fund you?
2) Are they teaching what you want to learn?
3) Is it a happy place?Don't want to start a fight here- but schools vary by A LOT on these criteria.