As far as the Abraham and Isaac example goes, I think that is a pretty valid point. If someone in 2012 came as close as Abraham did to sacrificing their child then they would absolutely end up in a psych ward, and I would have a hard time sympathizing with them despite being a Christian. I think in that particular example it is worth noting that the "rules" of the old testament are quite different than those of modern times for a traditional Christian. Burnt offerings are obsolete since Jesus's death on the cross made them no longer necessary. That doesn't mean I have an answer for why that was "okay" for God to ask for that radical of a sacrifice in the Old Testament but is not okay now.
One could argue that God does require that we follow the laws of the land that we live in, provided they do not require us to deny Him as the ultimate King. Again, I am applying all of this to a traditional Christian according to what I know about the bible.
As Elvish said, I think we need to be really careful whenever someone claims to hear God speaking to them. We also need to be really careful when talking about isolated examples from the Bible. I know of a lot of people who have completely disregarded the bible because they took something out of context. There are a lot of cultural considerations when you are looking at scripture to try and answer these types of questions, and honestly it probably isn't wise to try and delve too deeply into this type of debate over the Internet for that reason...And hopefully I didn't say something too stupid because I tapped this out on my ipod touch after waking up too early from a night shift