all this budgeting is great - and very useful, i have a similar one set up in an excel spreadsheet..
one thing is being over looked i think - and that is the "if shit really gets f**ked up"
for example if u stack it and need to come up with $2k for the insurance excess,
if your waterpump goes and smashes into your radiator (happened to me in november 08)
etc etc..
basically the back up cash you need just in case something happens..
i always make sure i have around $2k sitting in an account that i can easily get to and withdraw in case the worst possible situation happens at the worst possible time - murphies law
just something to think about..