WHOA, I'm studying like mad for the CCNA. Taking it next week.
You have to get a 849 or higher out of 1000 to pass. 3 eSims which are cake and the rest are multiple choice/multiple answer. I definately recommend the 640-607 book and the 607 Flash Card set. That's what I'm using to study, along with some $100 software, and 2 other kids in my class used those and passed the CCNA with scores in the 900's.
There will be plenty of subnetting questions no matter what, but it's so easy. Just write everything in binary, do the simple ANDing operations, and you're set. ACL's are that simple too. Usually the questions are will this application/ip address be able to access this server/router, etc. The eSims are usually an interface shutdown administratively, no clockrate, or incorrect ip's/subnets on the interfaces.
CCNA is just the beginning. Then CCNP, and maybe CCIE. Ugh.. that's a hard test. Only 10% off all people who ever take it pass.